BACK TOTOP Browse A-ZSearchBrowse A-ZABCDEFGHIJKLMNOPQRSTUVWXYZ0-9 E-mail FormEmail ResultsName:Email address:Recipients Name:Recipients address:Message: Print-FriendlyBookmarksbookmarks-menuTSH testThyrotropin; Thyroid stimulating hormone; Hypothyroidism - TSH; Hyperthyroidism - TSH; Goiter - TSHA TSH test measures the amount of thyroid stimulating hormone (TSH) in your blood. TSH is produced by the pituitary gland. It prompts the thyroid gland to make and release thyroid hormones into the blood. How the Test is Performed A blood sample is needed. Other thyroid tests that may be done at the same time include:Blood sampleVenipuncture is the collection of blood from a vein. It is most often done for laboratory testing.ImageRead Article Now Book Mark Article T3 test (free or total) T3 testTriiodothyronine (T3) is a thyroid hormone. It plays an important role in the body's control of metabolism (the many processes that control the rate...ImageRead Article Now Book Mark Article T4 test (free or total) T4 testT4 (thyroxine) is the main hormone produced by the thyroid gland. A laboratory test can be done to measure the amount of free T4 in your blood. Fre...ImageRead Article Now Book Mark Article Anti-TPO (antibodies against thyroid peroxidase)Anti-TPOThyroid peroxidase is a type of protein (called an enzyme) that cells in the thyroid gland use to make thyroid hormone. If these enzymes leak out in...ImageRead Article Now Book Mark Article How to Prepare for the Test There is no preparation needed for this test. Ask your health care provider about any medicines you are taking that may affect the test results. Do not stop taking any medicines without first asking your provider.Medicines you may need to stop for a short time include:Amiodarone Dopamine Lithium Potassium iodide Prednisone or other glucocorticoid medicines The vitamin biotin (B7) can affect the results of the TSH test. If you take biotin, talk to your provider before you have any thyroid function tests. How the Test will Feel When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away. Why the Test is Performed Your provider will order this test if you have symptoms or signs of an overactive or underactive thyroid gland. It is also used to monitor treatment of these conditions.OveractiveHyperthyroidism is a condition in which the thyroid gland makes too much thyroid hormone. The condition is often called overactive thyroid.ImageRead Article Now Book Mark Article UnderactiveHypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone. This condition is often called underactive thyroid....ImageRead Article Now Book Mark Article Your provider may also check your TSH level if you are planning to get pregnant. Normal Results Normal values range from 0.5 to 5 microunits per milliliter (µU/mL).TSH values can vary during the day. It is best to have the test early in the morning. Experts do not fully agree on what the upper number should be when diagnosing thyroid disorders. Some labs will use a higher normal range limit for older people (even as high as 7 µU/mL).Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test results.If you are being treated for a thyroid disorder, your TSH level will likely be kept between 0.5 and 4.0 µU/mL, except when:A pituitary disorder is the cause of the thyroid problem. A low TSH may be expected. You have a history of certain types of thyroid cancer. A TSH value below the normal range may be best to prevent the thyroid cancer from coming back. A woman is pregnant. The normal range for TSH is different for women who are pregnant. Your provider may suggest that you take thyroid hormone, even if your TSH is in the normal range. What Abnormal Results Mean A higher-than-normal TSH level is most often due to an underactive thyroid gland (hypothyroidism). There are many causes of this problem.A lower-than-normal level may be due to an overactive thyroid gland, which can be caused by:Graves disease Graves diseaseGraves disease is an autoimmune disorder that leads to an overactive thyroid gland (hyperthyroidism). An autoimmune disorder is a condition that occ...ImageRead Article Now Book Mark Article Toxic nodular goiter or multinodular goiter Toxic nodular goiterToxic nodular goiter involves an enlarged thyroid gland. The gland contains areas that have increased in size and formed nodules. One or more of th...ImageRead Article Now Book Mark Article Too much iodine in the body (due to receiving iodine contrast used during imaging tests, such as CT scan) CT scanA computed tomography (CT) scan is an imaging method that uses x-rays to create pictures of cross-sections of the body. Related tests include:Abdomin...ImageRead Article Now Book Mark Article Taking too much thyroid hormone medicine or prescribed natural or over-the-counter supplements that contain thyroid hormone Use of certain medicines may also cause a lower-than-normal TSH level. These include glucocorticoids/steroids, dopamine, certain chemotherapy medicines, and opioid painkillers such as morphine. Risks There is little risk involved with having your blood taken.Veins and arteries vary in size from one person to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.Other risks associated with having blood drawn are slight, but may include:Excessive bleeding Fainting or feeling lightheaded Multiple punctures to locate veins Hematoma (blood buildup under the skin) HematomaA bruise is an area of skin discoloration. A bruise occurs when small blood vessels break and leak their contents into the soft tissue beneath the s...ImageRead Article Now Book Mark Article Infection (a slight risk any time the skin is broken)Open ReferencesReferencesFaix JD. Thyroid function testing (thyrotropin, triiodothyronine, and thyroxine). In: Robertson RP, ed. DeGroot's Endocrinology. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 68.Guber HA, Oprea M, Rusell YX. Evaluation of endocrine function. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 25.Pearce EN, Hollenberg AN. Thyroid. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 207.Salvatore D, Cohen R, Kopp PA, Larsen PR. Thyroid pathophysiology and diagnostic evaluation. In: Melmed S, Auchus RJ, Goldfine AB, Koenig RJ, Rosen CJ, eds. Williams Textbook of Endocrinology. 14th ed. Philadelphia, PA: Elsevier; 2020:chap 11.Wassner AJ, Smith JR. Thyroid development and physiology. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 601.AllVideoImagesTogEndocrine glands - illustration Endocrine glands release hormones (chemical messengers) into the bloodstream to be transported to various organs and tissues throughout the body. For instance, the pancreas secretes insulin, which allows the body to regulate levels of sugar in the blood. The thyroid gets instructions from the pituitary to secrete hormones which determine the rate of metabolism in the body (the more hormone in the bloodstream, the faster the chemical activity; the less hormone, the slower the activity).Endocrine glandsillustrationPituitary and TSH - illustration The pituitary secretes thyroid stimulating hormone (TSH), which stimulates the thyroid gland to secrete hormones that affect body metabolism.Pituitary and TSHillustrationEndocrine glands - illustration Endocrine glands release hormones (chemical messengers) into the bloodstream to be transported to various organs and tissues throughout the body. For instance, the pancreas secretes insulin, which allows the body to regulate levels of sugar in the blood. The thyroid gets instructions from the pituitary to secrete hormones which determine the rate of metabolism in the body (the more hormone in the bloodstream, the faster the chemical activity; the less hormone, the slower the activity).Endocrine glandsillustrationPituitary and TSH - illustration The pituitary secretes thyroid stimulating hormone (TSH), which stimulates the thyroid gland to secrete hormones that affect body metabolism.Pituitary and TSHillustration Tests for TSH test TSH testTSI testRelated Information Hyperthyroidism(Condition)Hypothyroidism - InDepth(In-Depth) Review Date: 2/28/2024 Reviewed By: Sandeep K. Dhaliwal, MD, board-certified in Diabetes, Endocrinology, and Metabolism, Springfield, VA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. 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TSH testThyrotropin; Thyroid stimulating hormone; Hypothyroidism - TSH; Hyperthyroidism - TSH; Goiter - TSHA TSH test measures the amount of thyroid stimulating hormone (TSH) in your blood. TSH is produced by the pituitary gland. It prompts the thyroid gland to make and release thyroid hormones into the blood. How the Test is Performed A blood sample is needed. Other thyroid tests that may be done at the same time include:Blood sampleVenipuncture is the collection of blood from a vein. It is most often done for laboratory testing.ImageRead Article Now Book Mark Article T3 test (free or total) T3 testTriiodothyronine (T3) is a thyroid hormone. It plays an important role in the body's control of metabolism (the many processes that control the rate...ImageRead Article Now Book Mark Article T4 test (free or total) T4 testT4 (thyroxine) is the main hormone produced by the thyroid gland. A laboratory test can be done to measure the amount of free T4 in your blood. Fre...ImageRead Article Now Book Mark Article Anti-TPO (antibodies against thyroid peroxidase)Anti-TPOThyroid peroxidase is a type of protein (called an enzyme) that cells in the thyroid gland use to make thyroid hormone. If these enzymes leak out in...ImageRead Article Now Book Mark Article How to Prepare for the Test There is no preparation needed for this test. Ask your health care provider about any medicines you are taking that may affect the test results. Do not stop taking any medicines without first asking your provider.Medicines you may need to stop for a short time include:Amiodarone Dopamine Lithium Potassium iodide Prednisone or other glucocorticoid medicines The vitamin biotin (B7) can affect the results of the TSH test. If you take biotin, talk to your provider before you have any thyroid function tests. How the Test will Feel When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away. Why the Test is Performed Your provider will order this test if you have symptoms or signs of an overactive or underactive thyroid gland. It is also used to monitor treatment of these conditions.OveractiveHyperthyroidism is a condition in which the thyroid gland makes too much thyroid hormone. The condition is often called overactive thyroid.ImageRead Article Now Book Mark Article UnderactiveHypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone. This condition is often called underactive thyroid....ImageRead Article Now Book Mark Article Your provider may also check your TSH level if you are planning to get pregnant. Normal Results Normal values range from 0.5 to 5 microunits per milliliter (µU/mL).TSH values can vary during the day. It is best to have the test early in the morning. Experts do not fully agree on what the upper number should be when diagnosing thyroid disorders. Some labs will use a higher normal range limit for older people (even as high as 7 µU/mL).Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test results.If you are being treated for a thyroid disorder, your TSH level will likely be kept between 0.5 and 4.0 µU/mL, except when:A pituitary disorder is the cause of the thyroid problem. A low TSH may be expected. You have a history of certain types of thyroid cancer. A TSH value below the normal range may be best to prevent the thyroid cancer from coming back. A woman is pregnant. The normal range for TSH is different for women who are pregnant. Your provider may suggest that you take thyroid hormone, even if your TSH is in the normal range. What Abnormal Results Mean A higher-than-normal TSH level is most often due to an underactive thyroid gland (hypothyroidism). There are many causes of this problem.A lower-than-normal level may be due to an overactive thyroid gland, which can be caused by:Graves disease Graves diseaseGraves disease is an autoimmune disorder that leads to an overactive thyroid gland (hyperthyroidism). An autoimmune disorder is a condition that occ...ImageRead Article Now Book Mark Article Toxic nodular goiter or multinodular goiter Toxic nodular goiterToxic nodular goiter involves an enlarged thyroid gland. The gland contains areas that have increased in size and formed nodules. One or more of th...ImageRead Article Now Book Mark Article Too much iodine in the body (due to receiving iodine contrast used during imaging tests, such as CT scan) CT scanA computed tomography (CT) scan is an imaging method that uses x-rays to create pictures of cross-sections of the body. Related tests include:Abdomin...ImageRead Article Now Book Mark Article Taking too much thyroid hormone medicine or prescribed natural or over-the-counter supplements that contain thyroid hormone Use of certain medicines may also cause a lower-than-normal TSH level. These include glucocorticoids/steroids, dopamine, certain chemotherapy medicines, and opioid painkillers such as morphine. Risks There is little risk involved with having your blood taken.Veins and arteries vary in size from one person to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.Other risks associated with having blood drawn are slight, but may include:Excessive bleeding Fainting or feeling lightheaded Multiple punctures to locate veins Hematoma (blood buildup under the skin) HematomaA bruise is an area of skin discoloration. A bruise occurs when small blood vessels break and leak their contents into the soft tissue beneath the s...ImageRead Article Now Book Mark Article Infection (a slight risk any time the skin is broken)Open ReferencesReferencesFaix JD. Thyroid function testing (thyrotropin, triiodothyronine, and thyroxine). In: Robertson RP, ed. DeGroot's Endocrinology. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 68.Guber HA, Oprea M, Rusell YX. Evaluation of endocrine function. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 25.Pearce EN, Hollenberg AN. Thyroid. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 207.Salvatore D, Cohen R, Kopp PA, Larsen PR. Thyroid pathophysiology and diagnostic evaluation. In: Melmed S, Auchus RJ, Goldfine AB, Koenig RJ, Rosen CJ, eds. Williams Textbook of Endocrinology. 14th ed. Philadelphia, PA: Elsevier; 2020:chap 11.Wassner AJ, Smith JR. Thyroid development and physiology. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 601.