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A TSH (Thyroid Stimulating Hormone) test is performed to check for thyroid gland malfunctions. The hypothalamus releases TRH (Thyrotopin Release Hormone). TRH then generates the pituitary gland to release TSH. Triiodothyronine (T3) and Thyroxin (T4) are produced by the thyroid once TSH instigates their release. Both an underactive and overactive thyroid can cause a multitude of health problems.
TSH (Thyroid Stimulating Hormone) is a hormone produced by the pituitary gland, and not by the thyroid as it may seem. The purpose of TSH is to stimulate the thyroid to produce more thyroid hormone. High TSH levels typically indicates that the body is not receiving enough thyroid hormone. A low TSH level is indicative of the body receiving too much thyroid hormone. Testing for T4, free T3 (Triiodothyronine) and thyroid antibodies can also be performed to ensure that the problem lies within the thyroid itself and not in the hypothalamus or the pituitary gland.
The tests are performed by drawing blood from the patient when ordered by a physician. It is typically ordered when the physician feels that the patient may have one of two conditions, hypothyroidism or hyperthyroidism. They are also performed on a routine basis for people who have already been diagnosed with either of the two conditions.
- TSH (Thyroid Stimulating Hormone) is a hormone produced by the pituitary gland, and not by the thyroid as it may seem.
- A low TSH level is indicative of the body receiving too much thyroid hormone.
L-Carnitine & Hypothyroidism
The normal range for TSH level is 0.4 to 4.0 mlU/L (milli-international units per liter). People without symptoms or signs of an abnormally functioning thyroid may have a TSH level of 2.0 mlU/L and T4 (Thyroxine) levels are still at risk of developing hypothyroidism in the future.
Hypothyroidism occurs when the thyroid functions at below normal levels and is often referred to as an underactive thyroid. A low level of TSH and high level of T4 (Thyroxine) indicate hypothyroidism. The Mayo Clinic states that hypothyroidism is more common in women, particularly in women over the age of 50. Chemical reactions are upset by hypothyroidism 1.
In early stages of hypothyroidism it is not uncommon to have little or no symptoms, however joint pain, obesity, heart disease and infertility can occur later. Hypothyroidism can be controlled by the proper dosage of synthetic thyroid hormone.
- Hypothyroidism occurs when the thyroid functions at below normal levels and is often referred to as an underactive thyroid.
- In early stages of hypothyroidism it is not uncommon to have little or no symptoms, however joint pain, obesity, heart disease and infertility can occur later.
What Is Third Generation TSH?
Hyperthyroidism, also known as overactive thyroid, occurs when T4 levels are overproduced by the thyroid while TSH is either extremely low or nonexistent. An accelerated metabolism is one sign of an overactive thyroid, causing someone to feel irritable, sudden and rapid weight loss, rapid or irregular heart rate, sweating and nervousness are other symptoms. Several methods exist for treating hyperthyroidism, from anti-thyroid medications to radioactive iodine, which helps to slow down the rate at which the thyroid produces T4.
Complications of High TSH Levels
If left untreated, a high TSH level can lead to a number of larger problems. Hashimoto's Thyroiditis occurs when the immune system attacks the thyroid. A goiter occurs when the thyroid is left untreated and continues to enlarge and typically coincides with Hashimoto’s Thyroiditis.
Myxedema coma, although exceedingly atypical, can also occur when the thyroid is left untreated. Infertility, increased risk or heart disease, and birth defects are other complications that may happen when high TSH levels are left undiagnosed.
- If left untreated, a high TSH level can lead to a number of larger problems.
- Infertility, increased risk or heart disease, and birth defects are other complications that may happen when high TSH levels are left undiagnosed.
L-Carnitine & Hypothyroidism
What Is Third Generation TSH?
Symptoms of High TSH Levels
Hypothyroid Signs and Symptoms in Women
What Does a High TSH Level Mean?
Muscle Spasms With Thyroid Disorder
What Are the Causes of Fluctuating Thyroid Levels?
Thyroid Supplement Side Effects
Ferritin and Thyroid Function
The Signs & Symptoms of a Suppressed Thyroid
- American Thyroid Association. General Information/Press Room.
- Pirahanchi Y, Jialal I. Physiology, Thyroid Stimulating Hormone (TSH). In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. Updated April 25, 2019.
- AACC. Hashimoto Thyroiditis. Lab Tests Online. Updated October 18, 2019.
- DeGroot LJ. Graves’ Disease and the Manifestations of Thyrotoxicosis. [Updated 2015 Jul 11]. In: Feingold KR, Anawalt B, Boyce A, et al., editors. Endotext [Internet]. South Dartmouth (MA): MDText.com, Inc.; 2015.
- Nguyen QT, Lee EJ, Huang MG, Park YI, Khullar A, Plodkowski RA. Diagnosis and treatment of patients with thyroid cancer. Am Health Drug Benefits. 2015;8(1):30-40.
- Bindra A, Braunstein GD. Thyroiditis. Am Fam Physician. 2006;73(10):1769-76.
- Medeiros-Neto G. Multinodular Goiter. In: Feingold KR, Anawalt B, Boyce A, et al., editors. Endotext [Internet]. South Dartmouth (MA): MDText.com, Inc.; 2000-. Updated September 26, 2016.
- The National Institute of Diabetes and Digestive and Kidney Diseases. Hypothyroidism (Underactive Thyroid). Published August 2016.
- The National Institute of Diabetes and Digestive and Kidney Diseases. Hyperthyroidism (Overactive Thyroid). Published August 2016.
- Brent GA. Environmental exposures and autoimmune thyroid disease. Thyroid. 2010;20(7):755-61. doi:10.1089/thy.2010.1636
- Mcaninch EA, Bianco AC. The history and future of treatment of hypothyroidism. Ann Intern Med. 2016;164(1):50-6. doi:10.7326/M15-1799
- The National Institute of Diabetes and Digestive and Kidney Diseases. Grave’s Disease. Published September 2017.
- Stagnaro-Green, A., Abalovich, M, Alexander, E. et. al. Guidelines of the American thyroid association for the diagnosis and management of thyroid disease during pregnancy and postpartum. Thyroid. 2011(21)10. doi:10.1089/thy.2011.0087
- Liu G, Liang L, Bray GA, et al. Thyroid hormones and changes in body weight and metabolic parameters in response to weight loss diets: the POUNDS LOST trial. Int J Obes (Lond). 2017;41(6):878-886. doi:10.1038/ijo.2017.28
- Bahn R, Burch H, Cooper D, et al. Hyperthyroidism and other causes of thyrotoxicosis: Management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists. Endocrine Practice. 2011;17(3). doi:10.1089/thy.2010.0417
- Braverman L, Cooper D. Werner & Ingbar's The Thyroid, 10th Edition. WLL/Wolters Kluwer; 2012.
- Garber J, Cobin R, Gharib H, et. al. Clinical practice guidelines for hypothyroidism in adults: Cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association. Endocrine Practice. 2012;18(6). doi:10.1089/thy.2012.0205
- Haugen A, Alexander K., Bible K, et. al. 2015 American Thyroid Association Management guidelines for adult patients with thyroid nodules and differentiated thyroid cancer. Thyroid. 2016;26(1):1-133. doi:10.1089/thy.2015.0020
- Smallridge R, Ain K, Asa S, et. al. American Thyroid Association guidelines for management of patients with anaplastic thyroid cancer. Thyroid. 2012;22(11). doi:10.1089/thy.2012.0302
- Wells, S, Asa S, Dralle H, et. al. Revised American Thyroid Association guidelines for the management of medullary thyroid carcinoma. Thyroid. 2015;25(6). doi:10.1089/thy.2014.0335
Felicia Anderson is a freelance writer who lives in Virginia Beach, Virginia. She spent 3 years in the US Navy as an Aviation Ordnanceman. She also was sports editor of her high school newspaper and has had articles published in the Burkburnett Informer Star. She has attended Medical Careers Institute and Vernon College.