The TSH test contains 1 test with 4 biomarkers.
Brief Description: The TSH (Thyroid Stimulating Hormone) test measures the level of TSH in the blood. TSH is a hormone produced by the pituitary gland that regulates the production of thyroid hormones by the thyroid gland.
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: Specimen collection after fluorescein dye angiography should be delayed for at least 3 days. For patients on hemodialysis, specimen collection should be delayed for 2 weeks.
According to the assay manufacturer Siemens: "Samples containing fluorescein can produce falsely depressed values when tested with the Advia Centaur TSH3 Ultra assay."
When is a TSH test ordered?
A TSH test may be ordered in several situations to evaluate thyroid function:
Thyroid Function Evaluation: If a patient exhibits symptoms of thyroid dysfunction, such as fatigue, weight changes, or changes in mood, a TSH test may be ordered as part of a comprehensive thyroid function evaluation.
Monitoring Thyroid Hormone Therapy: For individuals receiving thyroid hormone replacement therapy, a TSH test helps assess the effectiveness of the treatment and ensures that TSH levels are within the target range.
Screening for Thyroid Disorders: In certain populations, such as newborns or pregnant women, a TSH test is used for screening purposes to detect thyroid disorders at an early stage.
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:
When a TSH test is ordered, several other tests may be included to provide a comprehensive evaluation of thyroid health. Here are some common tests ordered alongside a TSH test and the reasons for each:
Free T4 (Thyroxine):
- Purpose: To measure the level of T4, the primary hormone produced by the thyroid gland.
- Why Is It Ordered: T4 is converted to T3 (the more active thyroid hormone) in the body. Measuring Free T4 can help determine if the thyroid gland is producing an adequate amount of hormone in response to TSH.
Free T3 (Triiodothyronine):
- Purpose: To measure the level of T3, the active thyroid hormone.
- Why Is It Ordered: In some cases, especially in hyperthyroidism, T3 levels can be elevated even when T4 levels are normal.
Total T4 and Total T3:
- Purpose: To measure the total amount of T4 and T3 in the blood, including both bound and unbound (free) forms.
- Why Is It Ordered: These tests can give additional information about thyroid hormone production and binding.
Thyroid Peroxidase Antibodies (TPOAb) and Thyroglobulin Antibodies (TgAb):
- Purpose: To detect antibodies against thyroid proteins, indicative of autoimmune thyroid diseases like Hashimoto’s thyroiditis or Graves' disease.
- Why Is It Ordered: The presence of these antibodies can help diagnose autoimmune thyroid conditions, which can affect thyroid function and hormone levels.
Reverse T3 (rT3):
- Purpose: To measure the level of rT3, an inactive form of the hormone.
- Why Is It Ordered: Sometimes ordered in complex cases of thyroid dysfunction or in critically ill patients to assess thyroid hormone metabolism.
Calcium and Phosphorus:
- Purpose: To assess levels of calcium and phosphorus, as thyroid dysfunction can impact calcium metabolism.
- Why Is It Ordered: Hyperthyroidism can sometimes cause elevated calcium levels, and these tests can be part of a broader metabolic assessment.
Liver Function Tests:
- Purpose: To evaluate liver health, as liver disease can affect thyroid hormone metabolism.
- Why Is It Ordered: Liver dysfunction can alter the levels of thyroid hormones and binding proteins.
Sex Hormone Binding Globulin (SHBG):
- Purpose: To measure levels of SHBG, which can be influenced by thyroid hormone levels.
- Why Is It Ordered: Elevated levels of SHBG can be seen in hyperthyroidism and can sometimes be used as an indirect marker of thyroid hormone activity.
Complete Blood Count (CBC):
- Purpose: To provide a general overview of health and detect conditions like anemia.
- Why Is It Ordered: Anemia and other hematological conditions can sometimes be related to thyroid dysfunction.
These tests, when combined with a TSH test, can provide a comprehensive assessment of thyroid function and help diagnose thyroid disorders, monitor treatment efficacy, and identify potential complications. The specific tests chosen will depend on the individual's symptoms, medical history, and the results of the initial TSH test
Conditions where a test TSH is recommended:
A TSH test is commonly ordered for:
Hypothyroidism: Hypothyroidism refers to an underactive thyroid gland, resulting in insufficient production of thyroid hormones. A TSH test is essential in diagnosing hypothyroidism and monitoring the response to treatment.
Hyperthyroidism: Hyperthyroidism, on the other hand, denotes an overactive thyroid gland, leading to excessive production of thyroid hormones. A TSH test aids in diagnosing hyperthyroidism and assessing the effectiveness of treatment.
Thyroid Hormone Replacement Therapy: For individuals receiving thyroid hormone replacement therapy, a TSH test is crucial to ensure that TSH levels are within the desired therapeutic range, indicating the appropriate dosage of thyroid hormones.
How does my healthcare provider use a TSH test?
Healthcare providers use the results of a TSH test to:
Evaluate Thyroid Function: Abnormal TSH levels can indicate thyroid dysfunction, helping confirm the diagnosis of hypothyroidism or hyperthyroidism.
Monitor Thyroid Hormone Therapy: In individuals undergoing thyroid hormone replacement therapy, the TSH test helps determine if the treatment is achieving the desired therapeutic effect and allows adjustments to be made if necessary.
Assess Overall Thyroid Health: The TSH test, when considered in conjunction with other thyroid function tests, provides a comprehensive evaluation of thyroid health and aids in making informed decisions regarding patient care and interventions related to thyroid disorders.
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.
Most Common Questions About the TSH test:
Understanding the Test
What is the TSH test?
The TSH test is a blood test that measures the level of thyroid-stimulating hormone in your blood. TSH is produced by the pituitary gland in the brain and stimulates the thyroid gland to produce thyroid hormones T3 and T4.
Why is the TSH test done?
The TSH test is performed to evaluate the functioning of the thyroid gland. It can help diagnose conditions such as hyperthyroidism (overactive thyroid), hypothyroidism (underactive thyroid), or monitor the effectiveness of treatment for a thyroid disorder.
Interpreting the Results
What does a high TSH level indicate in the TSH test?
A high TSH level typically indicates that the thyroid gland is not producing enough thyroid hormones, a condition known as hypothyroidism. This could be due to a problem with the thyroid gland itself or with the pituitary gland that is not properly regulating TSH production.
What does a low TSH level indicate in the TSH test?
A low TSH level suggests that the thyroid gland is producing too much thyroid hormone, a condition known as hyperthyroidism. This can happen due to an overactive thyroid gland or if the pituitary gland is not properly signaling the thyroid to slow down hormone production.
About the Test
Can certain medications affect the results of the TSH test?
Yes, certain medications such as lithium, amiodarone, certain antidepressants, and some medications for hyperthyroidism can potentially affect the results of the TSH test. It's important to inform your healthcare provider of all the medications and supplements you're taking.
What factors can influence the results of the TSH test?
Various factors can influence the TSH test results including age, sex, pregnancy, stress, acute and chronic illnesses, and the time of day the test is performed as TSH levels fluctuate throughout the day.
Understanding the Implications
What role does TSH play in the body, as assessed by the TSH test?
TSH, produced by the pituitary gland, stimulates the thyroid gland to produce thyroid hormones T3 and T4. These hormones play critical roles in bodily functions like metabolism, growth, development, and body temperature regulation.
Can the TSH test give insight into my overall metabolic health?
Yes, the TSH test can provide insights into metabolic health. Abnormal TSH levels, indicating an underactive or overactive thyroid, can lead to a slow or fast metabolism respectively, affecting energy levels, weight, and overall health.
Risks and Precautions
Are there risks associated with having high or low TSH levels as indicated by the TSH test?
Yes, both high and low TSH levels can be indicative of an underlying thyroid disorder which if left untreated can lead to complications like heart problems, infertility, osteoporosis, and mental health issues.
Can the TSH test provide insight into my risk of developing certain diseases?
Yes, the TSH test can provide insight into your risk of developing diseases related to thyroid dysfunction. An overactive or underactive thyroid, indicated by abnormal TSH levels, can increase the risk of heart disease, bone disease (osteoporosis), infertility, and mental health conditions.
Dealing with Abnormal Results
What should I do if my TSH test shows high or low levels of TSH?
If your TSH test shows high or low levels, you should consult your healthcare provider for further evaluation and diagnosis. The treatment will depend on whether you have an underactive or overactive thyroid and the underlying cause.
Are there ways to manage high or low TSH levels as identified in the TSH test?
Yes, the treatment usually involves taking medication to restore the thyroid hormone levels to normal. For hypothyroidism, hormone replacement therapy is used, while hyperthyroidism may be treated with anti-thyroid medications, radioactive iodine, or in some cases, surgery.
Interpreting the Test Results
How are the results of the TSH test interpreted?
The results of the TSH test are compared to a reference range provided by the lab. A level above the upper limit of the reference range typically suggests hypothyroidism, while a level below the lower limit usually indicates hyperthyroidism.
Understanding the Test with Other Conditions
How does the TSH test relate to the diagnosis of Hashimoto's disease or Graves' disease?
Hashimoto's disease often presents with an elevated TSH level, while Graves' disease often presents with a lowered TSH level. The TSH test, along with tests for thyroid antibodies, can be used to diagnose these autoimmune thyroid disorders.
Does the TSH test help in diagnosing thyroiditis?
Yes, the TSH test can be useful in diagnosing thyroiditis. In the early inflammatory phase of thyroiditis, TSH might be low due to leakage of thyroid hormones into the blood. Later, as the thyroid becomes depleted of hormones, TSH may rise.
The Test in the Larger Context of Health
What is the relevance of the TSH test to overall health?
TSH test is important for assessing thyroid health, which is key to overall health. Thyroid hormones influence many body processes, including metabolism, growth and development, and body temperature. Abnormal TSH levels can indicate thyroid dysfunction, which can have wide-ranging effects on the body.
Does the TSH test provide insight intofertility issues?
Yes, both hyperthyroidism and hypothyroidism can affect menstrual cycles and ovulation, leading to difficulties with conception and increased risk of miscarriage. Hence, TSH testing can provide important insights if you're having trouble getting pregnant or maintaining a pregnancy.
Managing and Monitoring Thyroid Health
If I have a diagnosed thyroid disorder, will I need to take the TSH test regularly?
Yes, if you have a thyroid disorder, your healthcare provider will likely recommend regular TSH testing. The test can monitor the effectiveness of your treatment and determine whether medication adjustments are needed.
How is the TSH test used in the management of a thyroid disorder?
The TSH test is used to monitor the levels of thyroid-stimulating hormone, which helps evaluate the effectiveness of treatments for thyroid disorders like hypothyroidism and hyperthyroidism.
Can the TSH test be used to monitor my condition if I have Graves' disease?
Yes, the TSH test can be used to monitor Graves' disease. It helps evaluate how well your treatment is working and guide adjustments to your medication.
Living with Thyroid Disorders
What lifestyle changes might be recommended if the TSH test indicates a thyroid disorder?
Depending on the type of thyroid disorder, recommendations may include a balanced diet, regular exercise, stress management, and adequate sleep. If you have hypothyroidism, you may be advised to consume enough iodine in your diet.
What steps can I take to manage my symptoms if the TSH test indicates a thyroid disorder?
Management strategies will depend on whether you have hyperthyroidism or hypothyroidism. This can range from taking prescribed medications, adopting a healthy diet, engaging in regular exercise, and monitoring your symptoms closely.
Understanding the Test in Different Populations
Are certain people more likely to have abnormal TSH test results?
Yes, women, especially those over the age of 60, and people with a family history of thyroid disease are more likely to have abnormal TSH test results. In addition, individuals with certain autoimmune diseases like type 1 diabetes or rheumatoid arthritis are also at higher risk.
Does age affect the results of the TSH test?
Yes, TSH levels can naturally increase with age. The reference range for normal TSH can also vary depending on age. It's important for healthcare providers to interpret TSH results in the context of a person's age.
The Importance of Discussion a with Healthcare Provider
What should I discuss with my healthcare provider before getting the TSH test?
Before getting the TSH test, you should discuss your medical history, any symptoms you've been experiencing, and any medications you're currently taking. This will help your healthcare provider interpret your test results in the context of your overall health and lifestyle.
We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.