Myasthenia Gravis

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.

A synthetic circular peptide containing citrulline called CCP IgG (cyclic citrullinated peptide) has been found to be better at discriminating Rheumatoid Arthritis patients from other patients than either the perinuclear autoantibody test or the test for rheumatoid factor. Approximately 70% of patients with Rheumatoid Arthritis are positive for Anti-CCP IgG, while only about 2% of random blood donors and disease controls subjects are positive.

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Elevated RF is found in collagen vascular diseases such as SLE, rheumatoid arthritis, scleroderma, Sjögren's Syndrome, and in other conditions such as leprosy, tuberculosis, syphilis, malignancy, thyroid disease and in a significant percentage of otherwise normal elderly patients.

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The assay may be useful in the diagnosis of nonthyroidal illness (NTI). Patients with NTI have low T3 concentrations and increased concentrations of rT3. RT3 may be useful in neonates to distinguish euthyroid sick syndrome from central hypothyroidism.

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Total T3 measurements are used to diagnose and monitor treatment of hyperthyroidism and are essential for recognizing T3 toxicosis

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This test is used to diagnose hyperthyroidism and to clarify thyroid status in the presence of a possible protein binding abnormality.

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For diagnosis of hypothyroidism and hyperthyroidism.

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


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The free T4 are tests thelps evaluate thyroid function. The free T4 test is used to help diagnose hyperthyroidism and hypothyroidism. Free T4 is the active form of thyroxine and is usually ordered along with or following a TSH test. This helps the doctor to determine whether the thyroid hormone feedback system is functioning as it should, and the results of the tests help to distinguish between different causes of hyperthyroidism and hypothyroidism.

Thyroid Peroxidase Antibodies (TPO) and Thyroglobulin Antibodies

Measurement of thyroglobulin antibodies and thyroid peroxidase antibodies (TPO) is useful in the diagnosis and management of a variety of thyroid disorders including autoimmune thyroiditis, Hashimoto's Disease, Graves Disease and certain types of goiter.

 "IMPORTANT - Please note that Quest returns values up to 900 for the Thyroid Peroxidase Antibodies test.  If tracking requires values above 900 for the Thyroid Peroxidase Antibodies, then order test TPO Antibody Endpoint (Test Code # 15116).


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The Thyroid-stimulating Hormone (TSH) Blood Test is for differential diagnosis of primary, secondary, and tertiary hypothyroidism. The TSH test is also useful in screening for hyperthyroidism. This assay allows adjustment of exogenous thyroxine dosage in hypothyroid patients and in patients on suppressive thyroxine therapy for thyroid neoplasia.


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

Antinuclear antibodies are associated with rheumatic diseases including Systemic Lupus Erythematous (SLE), mixed connective tissue disease, Sjogren's syndrome, scleroderma, polymyositis, CREST syndrome, and neurologic SLE. 

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


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. 

Ulta Lab Tests provide comprehensive and affordable laboratory testing and health screening services directly to consumers. Our mission is to enable individual consumers across America to take control of their healthcare by having direct access to the quality lab tests of their choice. Consumers can now be proactive in the early detection and prevention of disease and do so with complete control of their healthcare costs.

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