What Is TSH Lab Work?

The thyroid is an organ in the neck which regulates hormones and metabolism in healthy individuals. If your doctor suspects that you have a thyroid condition, he may send you to the lab to have a TSH test performed.

TSH?

• TSH is short for thyroid stimulating hormone, which is manufactured in the pituitary gland. The U.S National Library of Medicine explains that the TSH hormone stimulates the thyroid and encourages the production of two other hormones in the body--triiodothyronine (T3) and thyroxine (T4).

Over or Under?

• A TSH test may be administered if symptoms are present that indicate an underactive or overactive thyroid. An underactive thyroid is referred to as hypothyroidism and an overactive thyroid is known as a hyperthyroidism---both can be detected in TSH lab work.

The Results

• According to The New York Times Health Guide, the TSH is administered at the vein by a health professional. A TSH test does not require you to fast and the lab work results are usually forwarded to your physician in two to three business days.

Explanation

• Lab Tests Online explains that the lab work will either show normal thyroid values or abnormal values, which denote a thyroid condition. TSH, T3 and T4 values are all taken into consideration when a diagnosis is determined.

Hypothyroidism

• TSH lab work that reveals normal T3 and T4 values, but a high TSH, is indicative of mild hypothyroidism. On the other hand, a low T3 and T4 result, in addition to a high TSH value will often indicate a more severe case of hypothyroidism.

Hyperthyroidism

• Lab Tests Online explains that when TSH lab work indicates that T3 and T4 are both either normal or high, and the TSH is high, hyperthyroidism is often indicated. Low T3, low T4 and low TSH may indicate a pituitary problem or secondary hyperthyroidism.