TSH is produced by the pituitary gland and is part of the body's system to maintain correct amounts of the thyroid hormones thyroxine (T4) and triiodothyronine (T3) in the blood and to help control the rate at which the body uses energy.
The thyroid-stimulating hormone (TSH) test is the most common test for evaluating thyroid function and/or symptoms of a thyroid disorder.
Read more about TSH Blood test.
The TSH test cannot be used as a complete test of thyroid function by itself since a normal TSH does not exclude thyroid-related problems. TSH is produced by the pituitary gland in the brain, so it is more a marker for pituitary function than thyroid function.
TSH can be normal for years even in the presence of high thyroid antibodies which indicate ongoing thyroid inflammation. For those with symptoms of potential thyroid issues, we recommend a full thyroid package for initial assessment of thyroid function in this test as a re-test of TSH, or extra test and suggest that anyone with suspected thyroid problems takes the full thyroid package to test free T3, free T4 and ideally also thyroid antibodies.
The normal range for TSH is controversial. Most labs still consider the upper range to be between 4 and 5 mU/L. In 2003, the American Association of Clinical Endocrinologists recommended lowering the reference range to 0.3-3 mU/L, but clinical guidelines were not changed.
In America, the mean TSH level is 1.5 in patients without known thyroid disease and many doctors find that their patients feel their best at an upper limit of 1.5-2 mU/L.
This test requires a blood draw, which can be done at your local clinic. It will be analysed by an accredited lab, such as Karolinska, Synlab, or Unilabs. The first results are usually available within 48h.
On the Day
Remember to take I.D. with you when going to take a test. Do not take your thyroid medication until after you have taken this test.
What happens next?
The lab sends the results to your personal dashboard, with comments from both a doctor and a nutritionist. If results are abnormal, we recommend seeing a doctor and, if appropriate, booking an appointment with a Nordic Wellth nutrition lifestyle specialist.
You may need to make lifestyle and dietary changes.