Myasthenia Gravis

Myasthenia Gravis Lab Tests and health information

The myasthenia gravis test can provide an accurate reading of the presence of anti–acetylcholine receptor (AChR) antibodies (Ab) and is reliable for diagnosing autoimmune myasthenia gravis. Order from Ulta Lab Tests to screen, analyze, and monitor for the muscle weakness condition myasthenia gravis with confidential results available in 24 to 48 hours online.      

Below the list of tests is a guide that explains and answers your questions on what you need to know about myasthenia gravis tests, along with information on myasthenia gravis, signs, symptoms, and diagnosis.


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Useful in the diagnosis of Myasthenia Gravis

Myasthenia Gravis is a neurological disorder characterized by a decrease in acetylcholine receptors. Patients exhibit skeletal muscle weakness and fatigability. Approximately 80% of patients with Myasthenia Gravis, excluding ocular involvement only, have detectable acetylcholine receptor antibody.

Acetylcholine Receptor Binding Antibody
Acetylcholine Receptor Blocking Antibody
Acetylcholine Receptor Modulating Antibody


Clinical Significance:

Detection of antibodies to muscle-specific receptor tyrosine kinase (MuSK) (titer test).


Myasthenia Gravis (MG) is a neuromuscular disorder characterized by muscle weakness, most commonly due to autoantibody-mediated loss of functional acetylcholine receptors (AChR) in the neuromuscular junction. This assay aids in the differential diagnosis of MG-like muscle weakness, in differentiating between generalized MG and ocular MG, and in monitoring therapeutic response. If binding antibodies are negative, assays for blocking and modulating antibodies should be considered.

Myasthenia gravis (MG) is a neuromuscular disorder characterized by muscle weakness, most commonly due to autoantibody-mediated loss of functional acetylcholine receptors (AChR) in the neuromuscular junction. Modulating Antibody to AChR causes weakness by inhibiting or modulating binding to the receptors.

Myasthenia gravis (MG) is a neuromuscular disorder characterized by muscle weakness, most commonly due to autoantibody-mediated loss of functional acetylcholine receptors (AChR) in the neuromuscular junction. This assay is most useful when the acetylcholinesterase receptor modulating antibodies are positive. The assay for blocking antibodies is useful in monitoring response to therapy.

Anti-skeletal muscle antibody titers of >1: 80 have been reported to be present in the serum of 30% of patients with Myasthenia Gravis, 95% of patients with Myasthenia Gravis and thymoma, and 25% of patients with thymoma.

Description: Anti-CCP is a test that measure the amount of cyclic citrullinated peptide in the blood. Anti-CCP is an autobody and it can be used to determine the if a person has Rheumatoid Arthritis.

Also Known As: ACPA, Anti-CCP, Anti-citrulline Antibody, Anti-cyclic Citrullinated Peptide, Anti-Cyclic Citrullinated Peptide (CCP) Antibody IgG, CCP, CCP Antibody, Citrullinated Peptide (CCP) IgG, Cyclic Citrullinated Peptide Antibody, Cyclic Citrullinated Peptide CCP Antibody IgG.

Collection Method: Blood Draw

Specimen Type: Serum

Test Preparation: No preparation required

When is a Cyclic Citrullinated Peptide IgG Antibody test ordered?

When someone displays indications and symptoms that could be attributable to previously undiagnosed inflammatory arthritis or has been diagnosed with undifferentiated arthritis, a CCP antibody test is usually ordered along with an RF test. When clinical indications and symptoms lead a health practitioner to suspect RA, it may be ordered as a follow-up test following a negative RF test. In most cases, RA affects many joints in a symmetrical pattern. The following are possible signs and symptoms:

  • Painful, heated, swollen joints in the hands and wrists.
  • Pain that affects the neck, shoulds, elbows, hips, knees, and/or feet.
  • In the morning, affected joints are stiff, although this improves over the day.
  • Fatigue
  • Fatigue
  • Underneath the skin, nodules form, especially at the elbows
  • An overall sensation of unwellness

What does a Cyclic Citrullinated Peptide IgG Antibody blood test check for?

Cyclic citrullinated peptide antibodies are autoantibodies directed against cyclic citrullinated peptides produced by the immune system. Anti-CCP antibodies are detected and measured in the blood with this test.

Citrulline is created in the body as a byproduct of the amino acid arginine metabolism. This conversion may occur at a faster rate in joints with rheumatoid arthritis. Citrulline alters the structure of proteins, triggering an immunological response that results in the production of autoantibodies against joint proteins. The CCP antibody test aids in the diagnosis of RA and can help identify persons with the disease's more quickly erosive type.

RA is a chronic, systemic autoimmune disease that affects the hands, foot, and other joints throughout the body, causing inflammation, discomfort, stiffness, and degenerative changes. It can strike anyone at any age, but it commonly strikes between the ages of 40 and 60, with women accounting for roughly 75 percent of those affected. The prognosis and course of RA are both unpredictable. It could take a long time to develop and progress, or it could happen quickly. In some people, it may go into remission, and in others, it may completely disappear. If left untreated, RA can impair a person's life expectancy and render many people unable to work within a few years.

There are a number of treatments available to help reduce the difficulties of RA, but they all hinge on getting a proper diagnosis and starting treatment before severe joint damage occurs. The basic blood test for detecting RA and distinguishing it from other types of arthritis and other inflammatory processes has been rheumatoid factor. However, RF's sensitivity and specificity aren't optimal; it can be negative in persons with RA symptoms but positive in those who don't. According to studies, the CCP antibody test has a sensitivity and specificity that is comparable to or better than RF, and it is more likely to be positive in patients with early RA.

CCP antibody testing, along with RF, is included in the American College of Rheumatology's (ACR) 2010 Rheumatoid Arthritis Classification Criteria for diagnosing rheumatoid arthritis. CCP antibodies can be found in roughly 50-60% of persons with early RA, as early as 3-6 months following the onset of symptoms, according to the ACR. Early detection and diagnosis of RA allows healthcare practitioners to start aggressive treatment early on, reducing complications and tissue damage.

Lab tests often ordered with a Cyclic Citrullinated Peptide IgG Antibody test:

  • Rheumatoid Factor
  • Sed Rate (ESR)
  • C-Reactive Protein
  • ANA

Conditions where a Cyclic Citrullinated Peptide IgG Antibody test is recommended:

  • Rheumatoid Arthritis
  • Autoimmune Disorders

How does my health care provider use a Cyclic Citrullinated Peptide IgG Antibody test?

To help diagnose rheumatoid arthritis and assess the severity and likely course of the disease, a cyclic citrullinated peptide antibody test may be ordered in conjunction with or after a rheumatoid factor test. Inflammatory indicators such as ESR and C-reactive protein may also be tested at this time.

Cyclic citrullinated peptide antibodies are autoantibodies directed against cyclic citrullinated peptides produced by the immune system.

CCP antibody testing may also be conducted to assess the likelihood of RA developing in persons with undifferentiated arthritis, or those who have symptoms that imply RA but do not yet fulfill the American College of Rheumatology's criteria. According to the American College of Rheumatology, roughly 95% of persons with a positive CCP antibody will develop RA in the future. It is critical to discover RA early in order to make informed treatment recommendations.

What do my CCP Antibody test results mean?

When persons with arthritis symptoms test positive for both CCP antibody and RF, they almost certainly have RA and are at risk of developing a more rapidly progressing and severe version of the illness. When patients show clinical indications of RA and are positive for CCP antibody but not RF, or have low levels of both, it is likely that they have early RA or will develop RA in the future.

When people have a positive RF but no CCP antibody, clinical signs and symptoms are more important in evaluating whether they have RA or another inflammatory illness. It is less likely that someone gets RA if they are negative for both CCP antibody and RF. However, it should be noted that RA is a clinical diagnosis that can be made even if autoantibody testing are negative.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.


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Description: RF is a blood test that is measuring the amount of rheumatoid factor that is present in the blood’s serum. It is used along with other tests to diagnose rheumatoid arthritis.

Also Known As: RF Test, Rheumatoid Arthritis Factor Test

Collection Method: Blood Draws

Specimen Type: Serum

Test Preparation: No preparation required

When is a Rheumatoid Factor test ordered?

When a person has RA signs and symptoms, an RF test may be ordered. Pain, warmth, swelling, and morning stiffness in the joints are common symptoms, as are nodules under the skin and, if the disease has progressed, signs of enlarged joint capsules and cartilage and bone loss on X-rays. When the first RF test is negative but the symptoms persist, the RF test may be repeated.

A cyclic citrullinated peptide antibody test may be ordered along with RF or if the RF result is negative to help diagnose RA in someone who has joint inflammation but does not yet fit the criteria for RA.

Additional autoimmune-related tests, such as an ANA, as well as other markers of inflammation, such as a CRP and Sed Rate, as well as a CBC to examine blood cells, may be ordered in addition to the RF test.

What does a Rheumatoid Factor blood test check for?

The autoantibody rheumatoid factor is an immunoglobulin M protein produced by the body's immune system. Autoantibodies attack a person's own tissues, mistaking them for "foreign" tissue. While the biological role of RF is unknown, its presence can be used to detect inflammatory and autoimmune activities. This test identifies and quantifies radiofrequency in the bloodstream.

The RF test is an important tool in the diagnosis of rheumatoid arthritis. A RF test will be positive in about 80% of people with RA. RF, on the other hand, can be found in persons with a range of different illnesses, including as Sjögren syndrome, as well as persistent bacterial, viral, and parasite infections, and some malignancies. It can be noticed in patients who have lung, liver, or kidney disease, and it can also be detected in a tiny percentage of healthy persons.

Lab tests often ordered with a Rheumatoid Factor test:

  • Cyclic Citrullinated Peptide Antibody
  • ANA
  • Sed Rate
  • C-Reactive Protein
  • Immunoglobulins

Conditions where a Rheumatoid Factor test is recommended:

  • Rheumatoid Arthritis
  • Autoimmune Disorders

How does my health care provider use a Rheumatoid Factor test?

The rheumatoid factor test is used to diagnose rheumatoid arthritis and to distinguish it from other types of arthritis or diseases that generate similar symptoms.

While the clinical picture is critical in the diagnosis of RA, some signs and symptoms, particularly in the early stages of the disease, may not be present or follow a predictable pattern. Additionally, the signs and symptoms may not always be easy to distinguish because people with RA may also have other connective tissue disorders such Raynaud phenomenon, scleroderma, autoimmune thyroid problems, and systemic lupus erythematosus and present symptoms of these disorders. When RA is suspected, the RF test is one of several tools that can be used to aid determine a diagnosis.

What do my Rheumatoid Factor test results mean?

The results of the RF test must be interpreted in the context of a person's symptoms and medical history.

The presence of large amounts of RF in persons with symptoms and clinical indications of rheumatoid arthritis indicates that they are likely to develop RA. Higher RF levels are associated with a worse prognosis and more severe illness.

A negative RF test does not rule out the possibility of RA. Around 20% of persons with RA will have very low levels of RF or none at all. In these circumstances, a positive CCP antibody test can be utilized to confirm RA.

Sjögren syndrome, systemic lupus erythematosus, sarcoidosis tuberculosis, syphilis, HIV/AIDS, hepatitis, scleroderma, infectious mononucleosis, cancers such as leukemia and multiple myeloma, or disease of the liver, lung, or kidney may all produce positive RF test These other disorders are neither diagnosed or monitored with the RF test.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.


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Description: A RT3 test is a laboratory test that checks for Reverse T3 levels in your blood’s serum.

Also Known As: T3 Reverse test, REVT3 Test, RT3 Test, T3R Test, Reverse T3 Test, Reverse Triiodothyronine Test

Collection Method: Blood Draw

Specimen Type: Serum

Test Preparation: No preparation required

When is this test ordered?

Reverse T3 is used to identify stress on the body due to many factors including extreme dieting, surgery, liver and kidney disease, insulin dependent diabetes, serious injury, and chronic alcohol consumption.

What is being tested?

Reverse T3 is a derivative of Thyroxine T4. T4 becomes the active thyroid hormone Triiodothyronine T3 when it loses one of its iodine atoms. T4 is also converted by the body into Reverse T3, which is an inactive version of T3 that lacks T3's metabolic function. Reverse T3 is thought to be produced by the body to conserve energy during times of severe illness and stress.

Related Tests and Panels:

  • T3 Free
  • T3 Total
  • T4 Free
  • T4 Total
  • TSH
  • T3 Uptake
  • Thyroid Peroxidase
  • Thyroglobulin Antibodies

Related Conditions:

  • Hyperthyroidism
  • Hypothyroidism
  • Hashimotos
  • Graves’ Disease
  • Autoimmune Diseases
  • Thyroid Cancer
  • Kidney Disease
  • Liver Disease
  • Alcoholism
  • Stress
  • Diabetes

How is the Reverse T3 test used by my healthcare provider?

Results of a Reverse T3 test are used in combination with results of T4 tests, T3 Tests, thyroid antibodies, and TSH in assessing a patient’s symptoms and thyroid function.

What does my Reverse T3 test result mean?

High levels of T3 Reverse indicate that an excessive amount of T4 is being converted into Reverse T3 instead of active T3. This can cause signs of hypothyroidism, a thyroid condition often referred to as underactive thyroid, even when other thyroid hormones are within normal ranges. Elevated levels of RT3 levels can also be a sign of illness and stress and as the body converts more T4 into Reverse T3 when experiencing illnesses and stress.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results


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Description: A T3 Total test is a blood test that measures triiodothyronine levels in your blood’s serum to evaluate your thyroid’s health and to screen for, diagnose, and monitor thyroid disorders such as hyperthyroidism.

Also Known As: Total T3 Test, Triiodothyronine Test, T3 Test, Bound T3

Collection Method: Blood Draw

Specimen Type: Serum

Test Preparation: No preparation required

When is a T3 Total test ordered?

When a person's TSH test results are abnormal, a total T3 test may be recommended. When a person has symptoms that imply hyperthyroidism, it may be requested as part of the investigational workup, especially if the free T4 level is not elevated.

The following are possible signs and symptoms:

  • Heart rate has increased.
  • Anxiety
  • Loss of weight
  • Sleeping problems
  • Hand tremors
  • Weakness
  • Diarrhea
  • Visual disturbances, light sensitivity
  • Puffiness around the eyes, dryness, discomfort, and, in some cases, bulging of the eyes are all possible side effects.

Total T3 may be ordered at regular intervals to monitor a known thyroid disease or to assess the efficacy of hyperthyroidism treatment.

What does a T3 Total blood test check for?

T3 is one of two key hormones produced by the thyroid gland, a small butterfly-shaped organ near the base of the throat that sits flat across the windpipe. Thyroxine is the other primary thyroid hormone, and together they help govern the rate at which the body utilizes energy. T3 in the blood is almost entirely linked to protein. The remaining portion is free and is the hormone's physiologically active form. Tests can determine the amount of free T3 or total T3 in the blood.

A feedback system controls T3 and T4 production. The hypothalamus releases thyrotropin releasing hormone when thyroid hormone levels in the blood drop, which prompts the pituitary gland to create and release thyroid-stimulating hormone. The thyroid gland is thus stimulated to create and/or release more thyroid hormones as a result of TSH. T4 is the most common thyroid hormone produced. This hormone is generally inactive, but in the liver and other tissues, it is transformed into the considerably more active T3.

If the thyroid gland produces too much T4 and T3, the person may have symptoms like uneasiness, hand tremors, weight loss, sleeplessness, and puffiness around dry, itchy eyes. The person's eyes may be unable to move normally and appear to be glaring in some circumstances. The eyeballs may also appear to bulge in some circumstances.

If the thyroid gland does not produce enough thyroid hormones, the person may experience weight gain, dry skin, lethargy, and constipation, which are all signs and symptoms of hypothyroidism and a slower metabolism. Thyroid hormone levels in the blood might be low or high due to thyroid malfunction, or in rare cases, insufficient or excessive TSH production due to a pituitary issue.

Autoimmune illnesses are the most common causes of thyroid dysfunction. Hyperthyroidism is caused by Graves disease, but it can also be caused by thyroiditis, thyroid malignancy, or high TSH production. Total T3 can be used to diagnose and monitor the impact of certain disorders on thyroid hormone production.

Lab tests often ordered with a T3 Total test:

  • TSH
  • T3 Free
  • T4 Free
  • T4 Total
  • T3 Reverse
  • T3 Uptake
  • Thyroid Peroxidase
  • Thyroglobulin Antibodies

Conditions where a T3 Total test is recommended:

  • Hyperthyroidism
  • Hypothyroidism
  • Hashimotos
  • Graves’ Disease
  • Autoimmune Diseases
  • Thyroid Cancer

How does my health care provider use a T3 Total test?

Thyroid function is measured with a total triiodothyronine test. It's usually ordered to assist identify hyperthyroidism, but it can also be used to track a person's therapy for a thyroid problem.

Thyroid hormones T3 and T4 are generated by the thyroid gland. They aid in the regulation of the rate at which the body expends energy and are governed by a feedback system. Thyroid-stimulating hormone boosts T4 and T3 synthesis and release. The liver and other tissues convert T4 into T3 as needed.

The majority of T4 and T3 in the blood is attached to protein, while just a small amount is free. Total T4, free T4, total T3, and free T3 can all be measured in blood tests.

Because the majority of T3 is coupled to protein, total T3 can be influenced by protein levels and binding ability, but free T3 is unaffected. Some professional standards, however, advocate total T3, thus either test can be used to evaluate thyroid function. To assist diagnose Graves disease, an autoimmune illness that is the most prevalent cause of hyperthyroidism, free T3 or total T3 may be ordered together with thyroid antibodies.

Following an abnormal TSH, a total T3 test is generally done, especially if the free T4 test is not high.

What does my T3 Total Test result mean?

Thyroid hormone levels that are high or low suggest a mismatch between the body's needs and supplies, but they don't inform the doctor what's causing the excess or deficiency.

If someone is being treated for hyperthyroidism with anti-thyroid medication and their free or total T3 levels are normal, the medicine is likely beneficial in treating the illness. If the free or total T3 or free T4 levels are high, the medication isn't working to address the problem, and the person may be having hyperthyroidism symptoms.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results


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Description: A T3 Free test is a blood test that measures unbound triiodothyronine levels in your blood’s serum to evaluate your thyroid’s health and to screen for, diagnose, and monitor thyroid disorders such as hyperthyroidism.

Also Known As: Free T3 Test, Free Triiodothyronine Test, FT3 Test, T3F Test, Unbound T3 Test

Collection Method: Blood Draw

Specimen Type: Serum

Test Preparation: No preparation required

When is a T3 Free test ordered?

When a person's TSH test results are abnormal, a free T3 test may be recommended. When a person has symptoms that imply hyperthyroidism, it may be requested as part of the investigational workup, especially if the free T4 level is not elevated.

The following are possible signs and symptoms:

  • Heart rate has increased.
  • Anxiety
  • Loss of weight
  • Sleeping problems
  • Hand tremors
  • Weakness
  • Diarrhea
  • Visual disturbances, light sensitivity
  • Puffiness around the eyes, dryness, discomfort, and, in some cases, bulging of the eyes are all possible side effects.

Free T3 may be ordered at regular intervals to monitor a known thyroid disease or to assess the efficacy of hyperthyroidism treatment.

What does a T3 Free test check for?

T3 is one of two key hormones produced by the thyroid gland, a small butterfly-shaped organ near the base of the throat that sits flat across the windpipe. Thyroxine is the other primary thyroid hormone, and together they help govern the rate at which the body utilizes energy. T3 in the blood is almost entirely linked to protein. The remaining portion is free and is the hormone's physiologically active form. Tests can determine the amount of free T3 or total T3 in the blood.

A feedback system controls T3 and T4 production. The hypothalamus releases thyrotropin releasing hormone when thyroid hormone levels in the blood drop, which prompts the pituitary gland to create and release thyroid-stimulating hormone. The thyroid gland is thus stimulated to create and/or release more thyroid hormones as a result of TSH. T4 is the most common thyroid hormone produced. This hormone is generally inactive, but in the liver and other tissues, it is transformed into the considerably more active T3.

If the thyroid gland produces too much T4 and T3, the person may have symptoms like uneasiness, hand tremors, weight loss, sleeplessness, and puffiness around dry, itchy eyes. The person's eyes may be unable to move normally and appear to be glaring in some circumstances. The eyeballs may also appear to bulge in some circumstances.

If the thyroid gland does not produce enough thyroid hormones, the person may experience weight gain, dry skin, lethargy, and constipation, which are all signs and symptoms of hypothyroidism and a slower metabolism. Thyroid hormone levels in the blood might be low or high due to thyroid malfunction, or in rare cases, insufficient or excessive TSH production due to a pituitary issue.

Autoimmune illnesses are the most common causes of thyroid dysfunction. Hyperthyroidism is caused by Graves disease, but it can also be caused by thyroiditis, thyroid malignancy, or high TSH production. Total T3 can be used to diagnose and monitor the impact of certain disorders on thyroid hormone production.

Lab tests often ordered with a T3 Free test:

  • TSH
  • T3 Total
  • T4 Free
  • T4 Total
  • T3 Reverse
  • T3 Uptake
  • Thyroid Peroxidase
  • Thyroglobulin Antibodies

Conditions where a T3 Free test is recommended:

  • Hyperthyroidism
  • Hypothyroidism
  • Hashimotos
  • Graves’ Disease
  • Autoimmune Diseases
  • Thyroid Cancer

How does my health care provider use a T3 Free test?

Thyroid function is measured with a free triiodothyronine test. It's usually ordered to assist identify hyperthyroidism, but it can also be used to track a person's therapy for a thyroid problem.

Thyroid hormones T3 and T4 are generated by the thyroid gland. They aid in the regulation of the rate at which the body expends energy and are governed by a feedback system. Thyroid-stimulating hormone boosts T4 and T3 synthesis and release. The liver and other tissues convert T4 into T3 as needed.

The majority of T4 and T3 in the blood is attached to protein, while just a small amount is free. Total T4, free T4, total T3, and free T3 can all be measured in blood tests.

Because the majority of T3 is coupled to protein, total T3 can be influenced by protein levels and binding ability, but free T3 is unaffected. Some professional standards, however, advocate total T3, thus either test can be used to evaluate thyroid function. To assist in diagnosing Graves disease, an autoimmune illness that is the most prevalent cause of hyperthyroidism, free T3 or total T3 may be ordered together with thyroid antibodies.

Following an abnormal TSH, a free T3 test is generally done, especially if the free T4 test is not high.

What does my T3 Free result mean?

Thyroid hormone levels that are high or low suggest a mismatch between the body's needs and supplies, but they don't inform the doctor what's causing the excess or deficiency.

If someone is being treated for hyperthyroidism with anti-thyroid medication and their free or total T3 levels are normal, the medicine is likely beneficial in treating the illness. If the free or total T3 or free T4 levels are high, the medication isn't working to address the problem, and the person may be having hyperthyroidism symptoms.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results


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Description: A T4 Total test is a blood test that measures thyroxine free levels in your blood’s serum to evaluate your thyroid’s health and to screen for, diagnose, and monitor thyroid disorders such as hypothyroidism.

Also Known As: Total T4 Test, Total Thyroxine Test, T4 Test, T4, T4 Total Test, Bound T4 Test

Collection Method: Blood Draw

Specimen Type: Serum

Test Preparation: No preparation required

When is a T4 Total test ordered?

When a person exhibits symptoms of hyperthyroidism or hypothyroidism, a Total T4 test may be administered, especially if a TSH test result is abnormal.

Hyperthyroidism can cause the following signs and symptoms:

  • Heart rate has increased.
  • Anxiety
  • Loss of weight
  • Sleeping problems
  • Hand tremors
  • Weakness
  • Diarrhea
  • Visual disturbances, light sensitivity
  • Puffiness around the eyes, dryness, discomfort, and, in some cases, bulging of the eyes are all possible side effects.

Hypothyroidism can cause the following symptoms:

  • gaining weight
  • Skin that is dry
  • Constipation
  • Intolerance to the cold
  • Skin that is puffy
  • Hair loss
  • Fatigue
  • Women's menstrual irregularities

When a person is being treated for a thyroid problem, Total T4 testing, along with other thyroid tests, may be requested on a regular basis.

Thyroid testing will most likely be ordered early and late in the pregnancy, as well as for a period after delivery, to monitor the mother and baby in pregnant women with thyroid abnormalities.

In the United States, thyroid hormone screening is routinely performed on babies as part of newborn screening programs.

What does a T4 Total blood test check for?

The thyroid gland, a small butterfly-shaped structure that lays on the windpipe towards the bottom of the throat, produces one of two primary hormones: thyroxine. Triiodothyronine is the other primary thyroid hormone, and together they help govern the rate at which the body utilizes energy. T4 in the blood is almost entirely linked to protein. The remaining portion is free and is the hormone's biologically active form. This test determines how much Bound T4 is present in the blood.

A feedback loop controls T4 production. The hypothalamus releases thyrotropin releasing hormone, which encourages the pituitary gland to generate and release thyroid-stimulating hormone when the amount of T4 in the blood drops. The thyroid gland is thus stimulated to produce and/or release more T4 as a result of TSH. TSH release is blocked as T4 content in the blood rises.

T4 accounts for over 90% of thyroid hormones. The thyroid gland releases accumulated T4 into circulation when the body requires it. T4 is either free or bound to protein in the blood. The amount of free T4 in the body is just about 0.1 percent of total T4. In the liver or other tissues, T4 is converted to T3. T3, like T4, is mainly attached to protein, however the physiologically active forms of T3 and T4 are the free versions. Free T3 in circulation is 4 to 5 times more active than free T4.

Dry skin, weight gain, cold intolerance, weariness, and irregular menstruation are among signs of hypothyroidism that occur when the thyroid gland does not produce enough T4 due to thyroid malfunction or insufficient TSH. Myxedema, or severe untreated hypothyroidism, can cause heart failure, convulsions, and coma. Hypothyroidism in children can slow growth and sexual development.

When the thyroid gland generates too much T4, the rate of a person's body functions increases, resulting in hyperthyroidism symptoms such as anxiety, increased heart rate, difficulty sleeping, weight loss, puffiness and dry itchy eyes, and hand tremors.

The most prevalent causes of thyroid dysfunction are connected to autoimmune illnesses. Hyperthyroidism is caused by Graves disease, while hypothyroidism is caused by Hashimoto thyroiditis. Thyroiditis, thyroid malignancy, and excessive or insufficient TSH production can all induce hyperthyroidism or hypothyroidism. By measuring Total T4, the influence of these variables on thyroid hormone synthesis can be recognized and monitored.

Note: Free T4 Index (T7) will only be calculated and reported if test code code 861 (T3 Uptake) is ordered as well.

Lab tests often ordered with a T4 Total test:

  • TSH
  • T3 Total
  • T3 Free
  • T4 Free
  • T3 Reverse
  • T3 Uptake
  • Thyroid Peroxidase
  • Thyroglobulin Antibodies

Conditions where a T4 Total test is recommended:

  • Hyperthyroidism
  • Hypothyroidism
  • Hashimotos
  • Graves’ Disease
  • Autoimmune Diseases
  • Thyroid Cancer

How does my health care provider use a T4 Total test?

Total thyroxine tests are used to assess thyroid function and detect thyroid disorders, such as hyperthyroidism and hypothyroidism, after the thyroid stimulating hormone level has been found to be abnormal.

The thyroid gland produces T4 and another hormone called triiodothyronine. They aid in the regulation of the rate at which the body expends energy and are governed by a feedback system. TSH promotes the thyroid gland's synthesis and release of T4 and T3.

The majority of T4 and T3 in the blood is attached to protein, while just a small amount is free. Total T4, free T4, total T3, and free T3 can all be measured in blood testing. The total T4 test has been around for a long time, but it is influenced by the quantity of protein in the blood that can bind to the hormone. The active form of thyroxine, free T4, is unaffected by protein levels. Many people believe that the free T4 test is a more accurate reflection of thyroid hormone activity, and it has largely supplanted the total T4 test.

A Total T4 test can be used in conjunction with or after a TSH test, and occasionally with a free T3 test to:

  • Help diagnose the cause of hyperthyroidism and hypothyroidism by detecting too much or too little thyroid hormone.
  • Differentiate between thyroid disorders.
  • Assist in the diagnosis of pituitary diseases
  • Assist in the diagnosis of infertility in women
  • In an individual with a known thyroid condition, track the effectiveness of treatment.
  • Monitor patients with pituitary disease to ensure that their thyroid is still operating, and thyroid hormone medication should be monitored if it isn't.
  • Monitor patients with thyroid cancer whose tumors respond to TSH. TSH and T4 levels will be monitored on a regular basis to ensure that adequate thyroid hormone is being administered to maintain TSH low while keeping T4 high.

In the United States, babies are routinely tested for T4 and TSH levels to rule out congenital hypothyroidism, which can lead to mental retardation if left untreated.

Thyroid abnormalities can sometimes be detected using Total T4 and TSH, however professional opinions differ on who should be screened and when they should start.

Thyroid antibodies, as well as a Total T4 test, may be ordered if a health practitioner suspects someone has an autoimmune-related thyroid problem.

What does my T4 Total result mean?

In general, high total T4 levels suggest an overactive thyroid gland, while low total T4 levels suggest an underactive thyroid gland. The test results are not diagnostic in and of themselves, but they will urge the health care provider to conduct additional testing to determine the reason of the excess or deficiency.

A range of temporary and chronic thyroid disorders are linked to both decreased and increased total T4 levels. A pituitary gland issue could be indicated by low total T4 levels along with a low TSH level, or by high total T4 levels combined with a high TSH.

When thyroid tests are done to monitor treatment for thyroid or pituitary diseases, the results will tell the doctor whether the treatment is working and/or if a dose adjustment is required. People with hyperthyroidism, for example, have their total T4, total T3, and TSH levels examined on a regular basis while taking anti-thyroid medicines to ensure that the drugs are effective and to reduce doses if thyroid hormone levels fall too low. TSH and total T4 levels are monitored on a frequent basis in hypothyroid patients to ensure that the correct dose of thyroid hormone is being given to bring TSH levels back to normal.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.


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Description: A T4 Free test is a blood test that measures thyroxine free levels in your blood’s serum to evaluate your thyroid’s health and to screen for, diagnose, and monitor thyroid disorders such as hypothyroidism.

Also Known As: Free T4 Test, Free Thyroxine Test, FT4 Test, T4F Test, T4 Free Test, Unbound T4 Test

Collection Method: Blood Draw

Specimen Type: Serum

Test Preparation: No preparation required

When is a T4 Free test ordered?

When a person exhibits symptoms of hyperthyroidism or hypothyroidism, a free T4 test may be administered, especially if the TSH test is abnormal.

Hyperthyroidism can cause the following signs and symptoms:

  • Heart rate has increased.
  • Anxiety
  • Loss of weight
  • Sleeping problems
  • Hand tremors
  • Weakness
  • Diarrhea
  • Visual disturbances, light sensitivity
  • Puffiness around the eyes, dryness, discomfort, and, in some cases, bulging of the eyes are all possible side effects.

Hypothyroidism can cause the following symptoms:

  • gaining weight
  • Skin that is dry
  • Constipation
  • Intolerance to the cold
  • Skin that is puffy
  • Hair loss
  • Fatigue
  • Women's menstrual irregularities

When a person is being treated for a thyroid problem, free T4 testing, along with other thyroid tests, may be requested on a regular basis.

Thyroid testing will most likely be ordered early and late in the pregnancy, as well as for a period after delivery, to monitor the mother and baby in pregnant women with thyroid abnormalities.

In the United States, thyroid hormone screening is routinely performed on babies as part of newborn screening programs.

What does a T4 Free blood test check for?

The thyroid gland, a small butterfly-shaped structure that lays on the windpipe towards the bottom of the throat, produces one of two primary hormones: thyroxine. Triiodothyronine is the other primary thyroid hormone, and together they help govern the rate at which the body utilizes energy. T4 in the blood is almost entirely linked to protein. The remaining portion is free and is the hormone's biologically active form. This test determines how much free T4 is present in the blood.

A feedback loop controls T4 production. The hypothalamus releases thyrotropin releasing hormone, which encourages the pituitary gland to generate and release thyroid-stimulating hormone when the amount of T4 in the blood drops. The thyroid gland is thus stimulated to produce and/or release more T4 as a result of TSH. TSH release is blocked as T4 content in the blood rises.

T4 accounts for over 90% of thyroid hormones. The thyroid gland releases accumulated T4 into circulation when the body requires it. T4 is either free or bound to protein in the blood. The amount of free T4 in the body is just about 0.1 percent of total T4. In the liver or other tissues, T4 is converted to T3. T3, like T4, is mainly attached to protein, however the physiologically active forms of T3 and T4 are the free versions. Free T3 in circulation is 4 to 5 times more active than free T4.

Dry skin, weight gain, cold intolerance, weariness, and irregular menstruation are among signs of hypothyroidism that occur when the thyroid gland does not produce enough T4 due to thyroid malfunction or insufficient TSH. Myxedema, or severe untreated hypothyroidism, can cause heart failure, convulsions, and coma. Hypothyroidism in children can slow growth and sexual development.

When the thyroid gland generates too much T4, the rate of a person's body functions increases, resulting in hyperthyroidism symptoms such as anxiety, increased heart rate, difficulty sleeping, weight loss, puffiness and dry itchy eyes, and hand tremors.

The most prevalent causes of thyroid dysfunction are connected to autoimmune illnesses. Hyperthyroidism is caused by Graves disease, while hypothyroidism is caused by Hashimoto thyroiditis. Thyroiditis, thyroid malignancy, and excessive or insufficient TSH production can all induce hyperthyroidism or hypothyroidism. By measuring free T4, the influence of these variables on thyroid hormone synthesis can be recognized and monitored.

Lab tests often ordered with a T4 Free test:

  • TSH
  • T3 Total
  • T3 Free
  • T4 Total
  • T3 Reverse
  • T3 Uptake
  • Thyroid Peroxidase
  • Thyroglobulin Antibodies

Conditions where a T4 Free test is recommended:

  • Hyperthyroidism
  • Hypothyroidism
  • Hashimotos
  • Graves’ Disease
  • Autoimmune Diseases
  • Thyroid Cancer

How does my health care provider use a T4 Free test?

Free thyroxine tests are used to assess thyroid function and detect thyroid disorders, such as hyperthyroidism and hypothyroidism, after the thyroid stimulating hormone level has been found to be abnormal.

The thyroid gland produces T4 and another hormone called triiodothyronine. They aid in the regulation of the rate at which the body expends energy and are governed by a feedback system. TSH promotes the thyroid gland's synthesis and release of T4 and T3.

The majority of T4 and T3 in the blood is attached to protein, while just a small amount is free. Total T4, free T4, total T3, and free T3 can all be measured in blood testing. The total T4 test has been around for a long time, but it is influenced by the quantity of protein in the blood that can bind to the hormone. The active form of thyroxine, free T4, is unaffected by protein levels. Many people believe that the free T4 test is a more accurate reflection of thyroid hormone activity, and it has largely supplanted the total T4 test.

A free T4 test can be used in conjunction with or after a TSH test, and occasionally with a free T3 test to:

  • Help diagnose the cause of hyperthyroidism and hypothyroidism by detecting too much or too little thyroid hormone.
  • Differentiate between thyroid disorders.
  • Assist in the diagnosis of pituitary diseases
  • Assist in the diagnosis of infertility in women
  • In an individual with a known thyroid condition, track the effectiveness of treatment.
  • Monitor patients with pituitary disease to ensure that their thyroid is still operating, and thyroid hormone medication should be monitored if it isn't.
  • Monitor patients with thyroid cancer whose tumors respond to TSH. TSH and T4 levels will be monitored on a regular basis to ensure that adequate thyroid hormone is being administered to maintain TSH low while keeping T4 high.

In the United States, babies are routinely tested for T4 and TSH levels to rule out congenital hypothyroidism, which can lead to mental retardation if left untreated.

Thyroid abnormalities can sometimes be detected using free T4 and TSH, however professional opinions differ on who should be screened and when they should start.

Thyroid antibodies, as well as a free T4 test, may be ordered if a health practitioner suspects someone has an autoimmune-related thyroid problem.

What does my T4 Free result mean?

In general, high free T4 levels suggest an overactive thyroid gland, while low free T4 levels suggest an underactive thyroid gland. The test results are not diagnostic in and of themselves, but they will urge the health care provider to conduct additional testing to determine the reason of the excess or deficiency.

A range of temporary and chronic thyroid disorders are linked to both decreased and increased free T4 levels. A pituitary gland issue could be indicated by low free T4 levels along with a low TSH level, or by high free T4 levels combined with a high TSH.

When thyroid tests are done to monitor treatment for thyroid or pituitary diseases, the results will tell the doctor whether the treatment is working and/or if a dose adjustment is required. People with hyperthyroidism, for example, have their free T4, free T3, and TSH levels examined on a regular basis while taking anti-thyroid medicines to ensure that the drugs are effective and to reduce doses if thyroid hormone levels fall too low. TSH and free T4 levels are monitored on a frequent basis in hypothyroid patients to ensure that the correct dose of thyroid hormone is being given to bring TSH levels back to normal.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.


Description: Thyroid Peroxidase and Thyroglobulin are blood tests used to detect thyroid antibodies to check for thyroid autoimmune disorders.

Also Known As: Thyroid Autoantibodies Test, Antithyroid Antibodies Test, Thyroid Peroxidase Antibody Test, Thyroperoxidase Antibody Test, TPO Test, Anti-TPO Test, Antithyroglobulin Antibody Test, TgAb Test

Collection Method: Blood Draw

Specimen Type: Serum

Test Preparation: No preparation required

When is a Thyroid Peroxidase and Thyroglobulin Antibodies test ordered?

When a person has irregular TSH and/or free T4 test results, symptoms of low or high thyroid hormone levels, or the appearance of a goiter, testing may be performed, especially if the reason is considered to be an autoimmune condition.

Hypothyroidism can produce a variety of symptoms, including:

  • Gaining weight
  • Fatigue
  • Skin that is dry
  • Hair loss
  • Cold intolerance
  • Constipation

Hyperthyroidism can produce symptoms such as:

  • Sweating
  • Heart rate that is quite fast
  • Anxiety
  • Tremors
  • Fatigue
  • Sleeping problems 
  • Sudden weight loss
  • Eyes that protrude

If a pregnant woman has a known autoimmune thyroid illness, or if another autoimmune disorder is suspected, one or more thyroid antibodies may be ordered early in the pregnancy and again at the end. These tests are performed to see if the newborn is at risk for thyroid problems. Thyroid antibodies can pass the placenta, causing hypothyroidism or hyperthyroidism in a newborn or developing kid.

Thyroid antibody testing may also be recommended if a person with another autoimmune condition has thyroid dysfunction symptoms and/or has reproductive problems that a healthcare provider suspects are caused by antibodies.

What does a Thyroid Peroxidase and Thyroglobulin Antibodies blood test check for?

Thyroid antibodies are antibodies that form when an individual's immune system incorrectly attacks the thyroid gland or thyroid protein components, causing chronic thyroid inflammation, tissue destruction, and/or thyroid function disruption. Specific thyroid antibodies in the blood are detected and quantified using laboratory techniques.

The thyroid gland is a tiny, butterfly-shaped gland in the throat that rests flat against the windpipe. Thyroxine and triiodothyronine, the two key hormones it generates, are critical in regulating the pace at which the body uses energy. Thyroid stimulating hormone stimulates the thyroid to generate T4 and T3 as needed by the body's feedback system. This mechanism aids in the maintenance of a reasonably constant level of thyroid hormones in the blood. Thyroid antibodies can cause chronic diseases and autoimmune disorders linked with hypothyroidism or hyperthyroidism, such as Graves disease or Hashimoto thyroiditis, when they interfere with this process.

Thyroid antibody testing includes the following:

  • Thyroid peroxidase antibody
  • Thyroglobulin antibody

Lab tests often ordered with a Thyroid Peroxidase and Thyroglobulin Antibodies test:

  • T3 Free
  • T3 Total
  • T4 Free
  • T4 Total
  • T3 Reverse
  • T3 Uptake
  • TSH

Conditions where a Thyroid Peroxidase and Thyroglobulin Antibodies test is recommended:

  • Hyperthyroidism
  • Hypothyroidism
  • Hashimotos
  • Graves’ Disease
  • Autoimmune Diseases
  • Thyroid Cancer

Commonly Asked Questions:

How does my health care provider use a Thyroid Peroxidase and Thyroglobulin Antibodies test?

Thyroid antibodies, such as thyroid peroxidase antibody, are tested to assist diagnose and differentiate autoimmune thyroid disease from other types of thyroid failure. Thyroid antibodies form when a person's immune system mistakenly targets thyroid gland or thyroid protein components, causing chronic thyroid inflammation, tissue destruction, and/or thyroid function disruption.

To aid in the diagnosis and/or monitoring of an autoimmune thyroid condition, one or more of the following tests may be used:

  • Thyroid peroxidase antibody, an antibody that targets thyroid peroxidase enzyme in the thyroid gland, can be seen in Graves disease and Hashimoto thyroiditis.
  • Thyroglobulin antibody is an antibody that targets thyroglobulin, the thyroid hormone's storage form.

These tests may be conducted to determine the reason of an enlarged thyroid or other symptoms linked to low or high thyroid hormone levels. When other thyroid test findings, such as total or free T3, free T4, and/or TSH, indicate thyroid dysfunction, testing may be done as a follow-up.

A thyroid antibody test or several thyroid antibody tests may be conducted to see if a person with an autoimmune disorder is at risk of thyroid dysfunction. Disorders like rheumatoid arthritis, systemic lupus erythematosus, and pernicious anemia can cause this.

A thyroglobulin test may be used to monitor someone who is being treated for thyroid cancer. The thyroglobulin antibody test is utilized in this scenario to see if the antibody is present in the person's blood and will interfere with the thyroglobulin level test.

What do my Thyroid Antibodies test results mean?

Negative test results show that thyroid antibodies were not detected in the blood at the time of testing, implying that symptoms are caused by anything other than autoimmune disease. However, antibodies are absent in a small number of persons with autoimmune thyroid disease. Repeat testing may be done at a later date if it is suspected that the antibodies will develop over time, as with several autoimmune illnesses.

Thyroid antibodies can be identified in a range of thyroid and autoimmune conditions, including thyroid cancer, type 1 diabetes, rheumatoid arthritis, pernicious anemia, and autoimmune collagen vascular diseases, with mild to moderately high levels.

Thyroid autoimmune disorders such as Hashimoto thyroiditis and Graves disease are usually associated with significantly elevated amounts.

Thyroid antibodies, in general, indicate the presence of an autoimmune thyroid illness, and the higher the level, the more likely it is. Antibody levels that grow over time may be more relevant than steady levels because they may suggest an increase in the severity of autoimmune illness. All of these antibodies can increase the risk of hypothyroidism or hyperthyroidism in a growing baby or infant if they are present in a pregnant mother.

If a person with thyroid cancer has thyroglobulin antibodies, the testing for thyroglobulin levels may be hampered. This could suggest that the thyroglobulin test can't be utilized as a tumor marker or to track a person's thyroid cancer progression. The presence of thyroglobulin antibodies has little effect on some testing procedures, including mass spectrometry. The thyroglobulin test can be utilized as a tumor marker when tested in these methods, regardless of whether or not thyroglobulin antibodies are present. If a method is utilized that is impacted by thyroglobulin antibodies, the antibodies' levels can be used as a tumor marker to monitor thyroid cancer. If they first remain high or fall low but then rise over time, the treatment was ineffective and the malignancy is likely to continue or recur. If the levels are dropping and/or have dropped to low or undetectable levels, the therapy is more likely to have been successful in eradicating the malignancy.

Thyroid antibodies can be found in a small percentage of patients who are otherwise healthy. The incidence of these antibodies is higher in women, increases with age, and implies an increased risk of developing thyroid illness in the future for thyroid peroxidase antibodies. If a person has a thyroid antibody but no obvious thyroid disease, the healthcare professional will monitor the person's health over time. While the majority of people will never have thyroid problems, a small percentage will.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.


Most Popular

Description: A TSH test is a blood test that measures thyroid stimulating hormone levels in your blood’s serum and is used to screen for and monitor treatment of thyroid disorders such as hypothyroidism and hyperthyroidism.

Also Known As: Thyroid Stimulating Hormone Test, Thyrotropin Test, TSH test, Thyroid Test, TSH Screen Test

Collection Method: Blood Draw

Specimen Type: Serum

Test Preparation: No preparation required

When is a TSH test ordered?

When a person has symptoms of hyperthyroidism or hypothyroidism, or an enlarged thyroid gland, a doctor may order a TSH test.

Hyperthyroidism can cause the following signs and symptoms:

  • Heart rate has increased.
  • Anxiety
  • Loss of weight
  • Sleeping problems
  • Hand tremors.
  • Weakness
  • Diarrhea
  • Visual disturbances, light sensitivity
  • Puffiness around the eyes, dryness, discomfort, and, in some cases, bulging of the eyes are all possible side effects.

Hypothyroidism can cause the following signs and symptoms:

  • gaining weight
  • Skin that is dry
  • Constipation
  • Intolerance to the cold
  • Skin that is puffy
  • Hair loss is a common problem.
  • Fatigue
  • Women's menstrual irregularities

When a person is being treated for a thyroid disease, TSH may be ordered at regular intervals. The American Thyroid Association suggests waiting 6-8 weeks after changing a person's thyroid medication dose before testing their TSH level again.

In the United States, TSH screening is routinely performed on newborns shortly after birth as part of each state's newborn screening program.

What does a TSH blood test check for?

The pituitary gland, a small structure beneath the brain and beyond the sinus cavities, produces thyroid-stimulating hormone. TSH causes thyroxine and triiodothyronine to be released into the bloodstream by the thyroid gland. These thyroid hormones aid in the regulation of the body's energy usage. This test determines how much TSH is present in the blood.

The feedback mechanism that the body utilizes to maintain consistent quantities of thyroid hormones in the blood includes TSH and its regulatory hormone, thyrotropin releasing hormone, which comes from the hypothalamus. TSH synthesis by the pituitary gland increases as thyroid hormone concentrations fall. TSH stimulates the thyroid gland, a small butterfly-shaped gland that lays flat against the windpipe at the base of the throat, to produce and release T4 and T3. Thyroid production turns on and off to maintain generally steady levels of thyroid hormones in the blood when all three organs are operating regularly.

When the thyroid produces excessive amounts of T4 and T3, the affected person may have hyperthyroidism symptoms such as high heart rate, weight loss, agitation, hand tremors, itchy eyes, and difficulty sleeping. The most prevalent cause of hyperthyroidism is Graves disease. It is a chronic autoimmune condition in which the immune system creates antibodies that mimic TSH, causing the thyroid hormone to be produced in excessive levels. As a result, the pituitary gland may produce less TSH, resulting in a low blood level.

Weight gain, dry skin, constipation, cold intolerance, and weariness are all symptoms of hypothyroidism, a condition in which the thyroid produces fewer thyroid hormones. In the United States, Hashimoto thyroiditis is the most prevalent cause of hypothyroidism. It's an autoimmune disease in which the immune system attacks the thyroid, causing inflammation and destruction as well as the generation of autoantibodies. The thyroid generates low levels of thyroid hormone in Hashimoto thyroiditis. The pituitary gland may create more TSH, resulting in a high blood level.

TSH values, on the other hand, do not necessarily indicate or predict thyroid hormone levels. TSH is produced abnormally in some persons and does not work properly. Despite having normal or modestly increased TSH values, they frequently develop hypothyroidism. Thyroid hormone levels can be high or low in a variety of thyroid illnesses, regardless of the amount of TSH in the blood.

TSH levels may be elevated or lowered in rare cases due to pituitary dysfunction. In addition to pituitary dysfunction, an issue with the hypothalamus can cause hyperthyroidism or hypothyroidism.

Lab tests often ordered with a TSH test:

  • T3 Free
  • T3 Total
  • T4 Free
  • T4 Total
  • T3 Reverse
  • T3 Uptake
  • Thyroid Peroxidase
  • Thyroglobulin Antibodies
  • Thyroid Panel

Conditions where a test TSH is recommended:

  • Hyperthyroidism
  • Hypothyroidism
  • Hashimotos
  • Graves’ Disease
  • Autoimmune Diseases
  • Thyroid Cancer

Commonly Asked Questions:

How does my health care provider use a TSH test?

Thyroid function and/or symptoms of a thyroid problem, such as hyperthyroidism or hypothyroidism, are frequently assessed with the thyroid-stimulating hormone test.

The pituitary gland, a small structure beneath the brain and beyond the sinus cavities, produces TSH. It's a part of the body's feedback system that keeps the thyroid hormones thyroxine and triiodothyronine in check and helps regulate the pace at which the body burns calories.

TSH tests are typically ordered in conjunction with or before a free T4 test. A free T3 test and thyroid antibodies are two further thyroid tests that can be ordered. TSH, free T4, and free T3 are sometimes ordered as part of a thyroid panel.

TSH is used to:

  • Diagnose a thyroid issue in a patient who is experiencing symptoms.
  • Check newborns for an underactive thyroid.
  • Monitor thyroid replacement therapy.
  • Monitor treatment of hyperthyroidism that involves medication.
  • Assist women in diagnosing and monitoring infertility issues.
  • Assist in determining the pituitary gland's function
  • Screen adults for thyroid issues and diseases.

What does my TSH blood test result mean?

A high TSH level could indicate that:

  • The person being examined has an underactive thyroid gland that isn't responding well to TSH stimulation owing to acute or chronic thyroid dysfunction.
  • If a person has hypothyroidism or has had their thyroid gland removed, the dose of thyroid hormone replacement medicine may need to be changed.
  • A patient with hyperthyroidism is taking too much anti-thyroid medication, and the dosage needs to be reduced.
  • There is a problem with the pituitary gland, such as a tumor that causes TSH levels to be out of control.

A low TSH level could imply the following:

  • An overactive thyroid gland
  • Thyroid hormone prescription taken in excess by patients being treated for an underactive thyroid gland.
  • Inadequate medication in an individual being treated for hyperthyroidism; nevertheless, after successful anti-thyroid treatment, TSH production may take a time to recover. This is why the American Thyroid Association recommends testing for thyroid hormones as well as TSH levels throughout treatment.
  • The pituitary gland has been damaged, preventing it from releasing enough TSH.

An abnormal TSH result, whether high or low, suggests an excess or deficiency in the quantity of thyroid hormone available to the body, but does not pinpoint the cause for the abnormal result. Additional testing is frequently performed after an abnormal TSH test result to determine the reason of the increase or decrease.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.


TSI stands for thyroid stimulating immunoglobulin. TSI tells the thyroid gland to swell and release excess amounts of thyroid hormone into the blood.

Description: An antinuclear antibody screening is a blood test that is going to look for a positive or negative result. If the result comes back as positive further test will be done to look for ANA Titer and Pattern. Antinuclear antibodies are associated with Lupus.

Also Known As: ANA Test, ANA Screen IFA with Reflex to Titer and pattern IFA Test, ANA with Reflex Test, Antinuclear Antibody Screen Test

Collection Method: Blood Draw

Specimen Type: Serum

Test Preparation: No preparation required

IMPORTANT Reflex Information: If ANA Screen, IFA is positive, then ANA Titer and Pattern will be performed at an additional charge of $13.00

When is an ANA Screen test ordered?

When someone exhibits signs and symptoms of a systemic autoimmune illness, the ANA test is requested. Symptoms of autoimmune illnesses can be vague and non-specific, and they can fluctuate over time, steadily deteriorate, or oscillate between periods of flare-ups and remissions.

What does an ANA Screen blood test check for?

Antinuclear antibodies are a type of antibody produced by the immune system when it is unable to differentiate between its own cells and foreign cells. Autoantibodies are antibodies that attack the body's own healthy cells, causing symptoms like tissue and organ inflammation, joint and muscle discomfort, and weariness. The moniker "antinuclear" comes from the fact that ANA specifically targets chemicals located in a cell's nucleus. The presence of these autoantibodies in the blood is detected by the ANA test.

The presence of ANA may be a sign of an autoimmune process, and it has been linked to a variety of autoimmune illnesses, the most common of which being systemic lupus erythematosus.

One of the most common tests used to detect an autoimmune disorder or rule out other conditions with comparable signs and symptoms is the ANA test. As a result, it's frequently followed by other autoantibody tests that can help establish a diagnosis. An ENA panel, anti-dsDNA, anti-centromere, and/or anti-histone test are examples of these.

Lab tests often ordered with an ANA Screen test:

  • ENA Panel
  • Sed Rate (ESR)
  • C-Reactive Protein
  • Complement
  • AMA
  • Centromere antibody
  • Histone Antibody

Conditions where an ANA Screen test is recommended:

  • Autoimmune Disorders
  • Lupus
  • Rheumatoid Arthritis
  • Sjogren Syndrome
  • Scleroderma

How does my health care provider use an ANA Screen test?

One of the most often performed tests to diagnose systemic lupus erythematosus is the antinuclear antibody test. It serves as the first step in the evaluation process for autoimmune diseases that might impact various body tissues and organs.

When a person's immune system fails to discriminate between their own cells and foreign cells, autoantibodies called ANA are created. They attack chemicals found in a cell's nucleus, causing organ and tissue damage.

ANA testing may be utilized in conjunction with or after other autoantibody tests, depending on a person's indications and symptoms and the suspected condition. Antibodies that target specific compounds within cell nuclei, such as anti-dsDNA, anti-centromere, anti-nucleolar, anti-histone, and anti-RNA antibodies, are detected by some of these tests, which are considered subsets of the general ANA test. In addition, an ENA panel can be utilized as a follow-up to an ANA.

These further tests are performed in addition to a person's clinical history to assist diagnose or rule out other autoimmune conditions such Sjögren syndrome, polymyositis, and scleroderma.

To detect ANA, various laboratories may employ different test procedures. Immunoassay and indirect fluorescent antibody are two typical approaches. The IFA is regarded as the gold standard. Some labs will test for ANA using immunoassay and then employ IFA to confirm positive or equivocal results.

An indirect fluorescent antibody is created by mixing a person's blood sample with cells attached to a slide. Autoantibodies in the blood bind to the cells and cause them to react. A fluorescent antibody reagent is used to treat the slide, which is then inspected under a microscope. The existence of fluorescence is observed, as well as the pattern of fluorescence.

Immunoassays—these procedures are frequently carried out using automated equipment, however they are less sensitive than IFA in identifying ANA.

Other laboratory tests linked to inflammation, such as the erythrocyte sedimentation rate and/or C-reactive protein, can be used to assess a person's risk of SLE or another autoimmune disease.

What do my ANA test results mean?

A positive ANA test indicates the presence of autoantibodies. This shows the presence of an autoimmune disease in someone who has signs and symptoms, but more testing is needed to make a definitive diagnosis.

Because ANA test results can be positive in persons who have no known autoimmune disease, they must be carefully assessed in conjunction with a person's indications and symptoms.

Because an ANA test can become positive before signs and symptoms of an autoimmune disease appear, determining the meaning of a positive ANA in a person who has no symptoms can take some time.

SLE is unlikely to be diagnosed with a negative ANA result. It is normally not required to repeat a negative ANA test right away; however, because autoimmune illnesses are episodic, it may be desirable to repeat the ANA test at a later date if symptoms persist.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.


Voltage-Gated Calcium Channel (VGCC) Type N Antibody

Clinical Significance

N-type calcium channel antibodies are more highly associated with primary lung cancer than P/Q-type. One or all of the autoantibodies in the myasthenia gravis (MG)/LEMS evaluation can occur with neoplasia without evidence of neurological impairment. One or both calcium channel antibodies (P/Q and N) can occur with paraneoplastic and idiopathic cerebellar ataxia, encephalomyeloneuropathies, and autonomic neuropathy. Classical symptoms of LEMS include proximal muscle weakness, fatigability, dry mouth and impotence. When presentation is further complicated with oculobulbar weakness, these symptoms can easily be misinterpreted as MG. However, because VGCC antibodies are positive in only approximately 5% of MG patients, the measurement of these antibodies is very useful in distinguishing LEMS from MG.

Alternative Name(s) 

N-VGCC,NCC



Myasthenia gravis (MG) is a chronic (long-term) autoimmune disorder where the body's immune system blocks communication between nerves and skeletal muscles. As a result, muscle fibers cannot properly activate, leading to muscle weakness. 

The best way to confirm an MG diagnosis is to perform a myasthenia gravis test of the patient's blood. This MG test will look for the unusual antibodies that are causing the nerve-muscle communication issues. Ulta Lab Tests has MG blood tests available for purchase today. 

The cause and risk factors of MG are not well understood yet. There is no prevention or cure. But, thankfully, most MG patients can be treated with drugs to tackle the antibody problem and regain strength in their muscles. MG will require a lifetime of care, but patients should live long high-quality lives.

The Basics of Muscle Contraction

At any given moment, your body is executing a huge number of skeletal muscle contractions to perform basic functions like keeping your eyes open or your head upright. Skeletal muscles are semi-autonomic, meaning these muscles sometimes perform a voluntary function (e.g., you consciously choose to close your eye), and other times involuntary (e.g., you blink without thinking about it).

Muscle contractions are made possible through nerve signals that communicate to muscle tissue via a chemical neurotransmitter called acetylcholine. The process works like this:

  1. Your body sends a pulse down a nerve until it hits the nerve end. 
  2. Then an acetylcholine neurotransmitter is released, travels through a tiny gap called the synapses, and reaches a muscle fiber. 
  3. The acetylcholine neurotransmitter is captured by an acetylcholine receptor sitting on the muscle fiber. 
  4. The contact between the acetylcholine and a receptor initiates muscle contraction. 

To keep your body functioning, your brain is subconsciously sending a vast number of nerve pulses every second through your body, creating a vast amount of acetylcholine jumping across synapses to reach receptors -- that is, unless you have MG. 

What Happens to Muscles in a Myasthenia Gravis (MG) Patient?

For those suffering from MG, their body's immune system produces an unusual type of protein, called an acetylcholine receptor antibody (AChR), that latches onto the acetylcholine receptors, blocking or destroying the receptors. Without receptors, the nerve cannot tell the muscle fiber to contract. 

When muscles cannot contract all fibers properly, the patient will feel weakness and rapid fatigue in those muscles. The misfiring of nerves could also cause uncontrollable twitching in specific muscles. 

What are the Symptoms of Myasthenia Gravis (MG)?

The general symptom for MG is muscle weakness and fatigue that continues to deteriorate further over time. But MG is called the "snowflake" disease because every patient tends to have their unique combination of symptoms, with MG impacting different muscles, at different severities, and different onset speeds.

Sometimes MG stays within one muscle group, such as with ocular myasthenia gravis in the eyes. It is also considered generalized myasthenia gravis and slowly spreads to other muscle areas.

The most common symptoms include:

  • Eye muscles: In 50%+ of MG patients, a problem with an eye muscle is the first symptom, such as:
  • Drooping of eyelids
  • Double vision
  • Face and throat muscles: The first symptom in about 15% of MG patients 
  • Impaired speaking
  • Difficulty swallowing, increase in choking, liquid coming out of the nose
  • Weakness and fatigue of the jaw muscles when chewing
  • Abnormal smile and facial expressions
  • Neck muscles
  • Difficulty holding up the head
  • Arm and leg muscles
  • Difficulty walking, holding objects

MG patients report sleep temporarily improves their muscle strength, only for the weakness and fatigue to creep back in during the day. 

Patients with MG should not feel any numbness in their body or suffer from any brain/memory issues, which would hint at an alternate explanation like nerve damage or circulatory problems. They should also not be experiencing weakness in involuntary muscles, such as dry mouth, constipation, and impotence, as this would hint instead to Lambert-Eaton myasthenic syndrome. 

Any person suffering any of the symptoms of MG needs to take additional steps to confirm if they have the disease.

How is a Myasthenia Gravis (MG) Diagnosis Confirmed?

The primary method of confirming a myasthenia gravis (MG) diagnosis is through a blood test, which seeks to locate the unusual acetylcholine receptor (AChR) antibodies in the bloodstream. Technically, there are three types of AChR antibodies that can be searched for:

  1. The kind of AChR that block receptors (90% of MG patients have these)
  2. The kind of AChR that modulate (alter/weaken) receptors (65% of MG patients have these)
  3. The kind of AChR that bind to receptors (40% of MG patients have these)

Given the "snowflake" nature of this disease, it is hard to guess which type of AChR antibody a person will have, so it is common for blood tests to look for one, two, or all three combinations of the above. 

In rare cases (about 5%), a patient will have seronegative myasthenia gravis, where there are zero antibodies detected, and additional types of blood tests will be needed to identify this scenario.

Laboratory Tests for MG 

The primary objectives of testing are to diagnose Myasthenia Gravis, differentiate it from other conditions that have similar symptoms, as well as to guide treatment. Also, some tests might be carried out to track an individual's health status over time.   

In general, laboratory testing might involve measuring one or more autoantibodies:  

  • Anti-MuSK (or muscle-specific kinase) antibodies are found in approximately 50-70% of those who have a negative status for AChR antibodies and also have generalized MG. 
  • AChR (or acetylcholine receptor) antibodies are found in up to 90% of those people with generalized MG and approximately 50% of those with ocular MG. AChR is MG's primary blood test. There are three kinds of AChR antibodies: blocking, binding (most frequently tested), and modulating.  
  • Anti-striated muscle antibodies are found in approximately 80% of those people with MG who also have an expanded thymus gland. The presence of these antibodies shows a significantly higher chance of the individual having a thymoma (usually a benign tumor in the thymus). 

Some other tests that might sometimes be performed are: 

What are the Risk Factors for Myasthenia Gravis (MG)?

Doctors have not found any known risk factors for myasthenia gravis (MG). At this point in our understanding of the disease, MG appears to strike randomly.

In general, the disease affects women more than men, and the peak of symptoms for women occurs before they hit 40 years old, while it peaks in men after they hit 60 years old.

There may be a genetic component that is not understood yet, so individuals with a family history of MG or other autoimmune disorders should carefully monitor themselves for symptoms and consider proactive blood testing.  

Doctors are also finding that individuals with thyroid problems and autoimmune conditions, such as rheumatoid arthritis or lupus are more likely to have MG.

What Causes Myasthenia Gravis (MG)?

Doctors are not exactly sure what causes the production of acetylcholine receptor (AChR) antibodies that create the symptoms of myasthenia gravis (MG). 

However, doctors have noticed that 75% of patients suffering from MG are also diagnosed with an enlarged thymus gland, and 10% have malignant (not cancerous) tumors on their thymus. The thymus gland is part of the immune system and sits in the upper chest behind the breastbone. It is believed to play a large role during infancy but gradually becomes less active by adulthood. 

This correlation between MG and an enlarged thymus has led doctors to believe the thymus gland is causing or exacerbating the production of AChR antibodies.

What Happens if Myasthenia Gravis (MG) Goes Untreated?

If left untreated, most generalized MG patients will continue to suffer worse weakening of their skeletal muscles. This will cause continued degradation of the quality of life, mobility, and the ability to self-care.

The worst-case result is that MG finally weakens the muscles that allow a person to breathe. This is called a myasthenic crisis and is a life-threatening condition requiring immediate emergency attention.

How is a Myasthenia Gravis (MG) Treated?

There is currently no way to prevent or cure myasthenia gravis (MG). However, the good news is that the symptoms of MG can be controlled, allowing MG patients to live long, high-quality lives. 

The primary methods of treating myasthenia gravis (MG) include:

  • Taking drugs that strengthen the acetylcholine neurotransmitter and receptors
  • Taking drugs that suppress the immune system in order to suppress the acetylcholine receptor (AChR) antibodies 
  • Removing the thymus gland
  • Having the patient's blood filtered to clean out the AChR antibodies 

The goal of the above treatments is to reduce the symptoms of MG and regain muscle strength in the skeletal muscles, especially in the muscles necessary for breathing. Even with treatment, it is still possible for symptoms to go through cycles of flare-ups and temporary remissions. 

Benefits of Using Ulta Lab Tests for Myasthenia Gravis (MG) Testing

The primary method of diagnosing MG myasthenia gravis is through a blood test that detects the unusual acetylcholine receptor (AChR) antibodies in the blood. Ulta Lab Tests has MG blood tests available for purchase today. 

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