Serum Total T4

Specimen Required

3-5cc Clotted Blood or Serum

Fasting Required

Purpose of the Test

Serum total T4 test is done to assess thyroid gland function. It is used to evaluate individuals who have symptoms of hyperthyroidism or hypothyroidism, and it can also help to monitor treatment of thyroid disorders.

When this test is required

It may be requested when a healthcare provider suspects that someone has a thyroid disorder or if they have been diagnosed with a thyroid disorder and are being treated with medication. It may also be ordered as part of routine health checkups or for monitoring treatment for a thyroid disorder.

What the Test Detects

Total T4 is a measure of the total amount of thyroxine in the blood. Thyroxine is one of the thyroid hormones produced by the thyroid gland. It is important for regulating metabolism in the body.

Preparation for the Test

There is no specific preparation required, but certain medications can interfere with the results, such as hormone replacement therapy, birth control pills, and steroids. It is important to tell the healthcare provider about any medications being taken before the test.

Sample Requirements

A blood sample is required for this test.

Additional Notes

This test measures the total amount of T4 in the blood, which includes both the active form and the inactive form of T4. A free T4 test may be ordered in addition to the total T4 test to measure the amount of active T4 in the blood.

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