Thyroid Stimulating Hormone (TSH) Ultrasensitive, Serum

TSH is secreted by the anterior pitutary which stimulates T3 and T4 formation and secretion. TSH along with thyroid hormones thyroxine (T4) and triiodothyronine (T3) control the basal metabolic rate. TSH measurement is done for screening of euthyroidism, screening of hypothyroidism in new born, diagnosis of hypo and hyperthyroidism and follow-up of T3 and T4 replacement therapy in hypothyroidism. The ultrasensitive thyroid-stimulating hormone (TSH) test is a useful test for evaluating the thyroid gland functional status, when suspecting or when there are symptoms of a thyroid disorders such as hyperthyroidism or hypothyroidism. A TSH blood test is ordered along with free T4, free T3 test and thyroid antibodies (if suspecting autoimmune thyroid disease) tests. Tsh ultrasensitive test helps to diagnose a symptomatic thyroid disorder, to screen newborns for hypothyroidism, monitor thyroid replacement therapy in hypothyroidism, monitor anti-thyroid treatment in hyperthyroidism, to diagnose and monitor infertility related issues in women, occasionally to evaluate the function of the pituitary gland. TSH is a more sensitive test when compared with TSH, for the early diagnosis of thyroid disorders with better precision and accuracy.

1. What are the conditions associated with hypo- and hyperthyroidism?

The most common causes of autoimmune-related thyroid disorders are like graves disease which causes hyperthyroidism and Hashimoto thyroiditis which causes hypothyroidism. Thyroiditis, thyroid cancer, and excessive or deficient production of TSH can cause both hyper and hypothyroidism.

2. What is goiter?

Goiter is abnormal enlargement of the thyroid gland and may be associated with hypo, hyper or euthyroidism.

3. What are the additional blood tests that may be performed?

Thyroid panel (T3, T4 and TSH) - to help diagnose and differentiate various thyroid disorders.

Thyroid auto - antibodies which help in differentiating different types of thyroiditis and identifying autoimmune thyroid conditions.

Calcitonin - Increased levels of calcitonin are seen in C-cell hyperplasia and medullary thyroid cancer.

Thyroglobulin - to monitor treatment of thyroid cancer.

4. How can I tell if my thyroid is working properly?

Both an underactive and overactive thyroid gland can cause symptoms. An enlarged thyroid gland either dissure or nodule, hoarseness of voice and symptoms like fatigue, depression, anxiety, weight loss or weight gain, temperature intolerances, hair loss, dryness of skin, or menstrual irregularities indicate a thyroid disorder.

5. Is uTSH measured during pregnancy?

uTSH is generally not measured in asymptomatic pregnant women. But uTSH is measured in those with symptoms and/or a known thyroid disorder at regular intervals to detect and evaluate functional status of thyroid (hyperthyroidism or hypothyroidism) both during pregnancy and after.