This is a thyroid hormone evaluation test which determines the increase (hyperthyroidism) or decrease (hypothyroidism) in the production of thyroid by pituitary gland. This test is widely used for the detection of various thyroid disorders, for monitoring the treatment of anti-thyroid therapy, for the detection of underactive thyroid in newborns and also for the screening and diagnosis of infertility issues in women. The clinical symptoms that act as prognosis of hyperthyroidism disorders include goiter, weight loss, shivering in hands, general weakness, visual disturbance and anxiety. The primary symptoms of hypothyroidism include weight gain, constipation, puffy and dry skin, fatigue and irregular periods in women.
If you present with any of the symptoms typical in thyroid disorders, then you will need a TSH lab test to check their levels. If a diagnosis of a thyroid-related disease is confirmed, testing TSH levels will be done regularly to monitor the levels and, at the same time, monitor the effects of the treatment so adjustments can be made. The interval between the TSH tests is typically six to eight weeks.
How to Prepare for a TSH Test
Procedures that used iodine dye, such as an X-ray that made use of an iodine-contrast material, have an effect on theTSH test range and values. So before you do a TSH test, you may want to wait a while till all traces of the contrast material have been eliminated from your system. Drinking lots of fluid will help you in flushing out the contrast material.
Medications could also influence the outcome of theTSH test. Medications that could potentially affect the thyroid test TSH range include dopamine, prednisone, and lithium. Glucocorticoid medication as well as amiodarone could also affect the values.
If you have had none of these, then you could proceed with the TSH reflex blood test where a blood sample will be taken to measure the TSH levels. Other tests may also be given together with the TSH reflex test to check for T3 and T4 levels (either free or total).
Of note, fasting is required before you do a TSH lab test, and it is best if you have the procedure early in the morning when the level is at its highest.
What the Results Mean
In adults, normal values may range from 0.4 mU/L to 4.2 mU/L. In newborn and children, they tend to be higher (1 to 39 mU/L in newborn and it drops down to 0.7 to 6.4 mU/L in children).
TSH level that is higher than normal could mean a thyroid gland that is producing too little thyroid hormones (hypothyroidism) and causing problems such as Hashimoto’s thyroiditis and pituitary tumor. It could also mean that the thyroid hormone treatment is inadequate.
TSH level that is lower than normal could mean that the thyroid gland is producing too much thyroid hormones (hyperthyroidism) and causing problems such as Graves’ disease, pituitary gland problem, and goiter. This could also mean that the dosages for the thyroid hormone treatment are too high.
Common TSH Test Questions
Is TSH test given to pregnant women?
Not to asymptomatic women since pregnancy sometimes affects the values, especially during the first trimester. But for those with known thyroid problems and has symptoms of a thyroid problem, this test may be given.
What does 3rd generation TSH test mean?
This is an ultrasensitive TSH test that can detect even the lowest amount of the hormone, despite high T3 or T4 hormone levels.
What are T3 and T4? And why are they important in TSH tests?
Both of these hormones are produced by the thyroid gland and important in metabolism, growth, and development. Their levels are frequently tested together with TSH levels to give a more accurate diagnosis of the thyroid problem.
LabEspy recommends Lab Testing API, Ulta Lab Tests, Walk-In Lab for this test.