Thyroid function tests are performed if there is a suspicion of an underactive or overactive thyroid. Samples are collected between 7–16. Thyroid function tests do not require fasting. If you are on thyroid medication, do not take the medicine before sampling on the sampling day. You should always take the follow-up tests around the same time of the day to ensure that the results are comparable. The treating physician is always responsible for interpreting your results.

Name and abbreviation of test: THYROTROPIN P -TSH

Thyrotropin (TSH) is a pituitary hormone that regulates thyroid gland function. Thyrotropin is essential to thyroxine (thyroid hormone) production. The test is a standard test to screen suspected hypothyroidism, which is indicated by high TSH levels in blood.

The reference ranges in P-TSH tests are

• 5–4.0 mU/l for adults aged 20–59
• 5–4.3 mU/l for adults aged 60–69
• 5–5.9 mU/l for adults aged 70–79
• 5–7.5 mU/l for adults aged 80 and over

Name and abbreviation of test: THYROXINE, FREE P -T4-V

Thyroxine is a thyroid hormone. This test is a standard test performed if there is a suspicion of an underactive or overactive thyroid. Decreased free thyroxine levels indicate hypothyroidism and elevated levels hyperthyroidism. The reference range in P -T4-V tests is 11.0–22.0 mU/L for adults aged 20 and over.