{"id":8102,"date":"2020-01-20T09:00:53","date_gmt":"2020-01-20T14:00:53","guid":{"rendered":"https:\/\/www.singlecare.com\/blog\/?p=8102"},"modified":"2021-07-29T11:18:15","modified_gmt":"2021-07-29T15:18:15","slug":"tsh-test","status":"publish","type":"post","link":"https:\/\/www.singlecare.com\/blog\/tsh-test\/","title":{"rendered":"What is a TSH test and what do your results mean?"},"content":{"rendered":"

The thyroid-stimulating hormone (TSH) test evaluates thyroid function and thyroid hormone levels. It\u2019s produced by the pituitary gland, which tells your thyroid, located in the lower front of your neck, to make and release hormones that control our body temperature, metabolism, and keep our brains, hearts, and other organs working properly.\u00a0<\/span><\/p>\n

The American Thyroid Association (ATA) recommends that adults begin TSH testing at the age of 35 and repeat tests every five years if results are in the normal range. Your doctor may also order a TSH test if you\u2019re experiencing symptoms of an underactive or overactive thyroid. Symptoms of hypothyroidism<\/a> (an underactive thyroid) can include fatigue, brain fog, extremely dry skin, hair loss, and feeling cold. <\/span>Symptoms<\/span><\/a> of hyperthyroidism (an overactive thyroid) can include sweating, a fast heart rate, muscle weakness, anxiety, and irritability. In either case, you\u2014or your healthcare provider\u2014might find that your thyroid is enlarged, which is called a goiter, or thyroid nodules, which are small lumps on the thyroid gland.<\/span><\/p>\n

What does the TSH test involve?\u00a0<\/span><\/h2>\n

The TSH blood test is often administered as part of a panel of blood tests in conjunction with an annual health exam. The test determines how well your thyroid is working by measuring the amount of thyroid-stimulating hormone in your blood. It\u2019s a non-fasting blood test, meaning you don\u2019t have to do anything special to prepare.\u00a0<\/span><\/p>\n

Physicians should take a TSH blood sample for thyroid patients every four to eight weeks after their initial diagnosis. The<\/span> ATA<\/span><\/a> recommends TSH testing every six to 12 months while you\u2019re on a stable medication dose and more often if your dose has changed.\u00a0<\/span><\/p>\n

What should your TSH level be?<\/span><\/h2>\n

Most laboratories classify normal TSH levels as between 0.4 and 4.5 milliunits per liter (mU\/L), according to the<\/span> American Thyroid Association<\/span><\/a> (ATA). A normal TSH level in most cases, usually indicates that you don\u2019t have a thyroid problem.<\/span><\/p>\n

The<\/span> ATA<\/span><\/a> reports that nearly 20 million Americans have some form of thyroid disease. Yet more than 60% of those with a thyroid disorder are unaware of their medical condition.\u00a0<\/span><\/p>\n

What does it mean when your TSH is low?<\/span><\/h3>\n

In most cases, TSH levels lower than 0.4 mU\/L indicate hyperthyroidism, also known as overactive thyroid, meaning, your body produces too much thyroid hormone. Graves\u2019 disease is an autoimmune disorder that sometimes causes hyperthyroidism.<\/span><\/p>\n

What happens when your TSH is high?<\/span><\/h3>\n

Generally, TSH levels higher than 4.5 mU\/L indicate hypothyroidism, or an underactive thyroid, meaning your body isn\u2019t making enough thyroid hormone. Hashimoto\u2019s thyroiditis is an autoimmune disorder that sometimes causes hypothyroidism.<\/span><\/p>\n

Can you still have a problem if your TSH is normal?<\/span><\/h2>\n

\u201cThe TSH test is a highly sensitive indicator of your overall thyroid health,\u201d says Brittany Henderson, MD, a board-certified endocrinologist at <\/span>Charleston Thyroid Center in Mount Pleasant, South Carolina<\/span><\/a>. \u201cInterpretation can be difficult because there is a wide range of \u2018normal\u2019 on the TSH scale.\u201d<\/span><\/p>\n

Medications and supplements you\u2019re currently taking can affect the results of your TSH test. One example is biotin, which can falsely show low TSH levels.<\/span><\/p>\n

What\u2019s considered normal is influenced by several factors:<\/span><\/p>\n