Thyroid-stimulating Hormone (TSH) CPT: 84443



Special Instructions

This test may exhibit interference when sample is collected from a person who is consuming a supplement with a high dose of biotin (also termed as vitamin B7 or B8, vitamin H, or coenzyme R). It is recommended to ask all patients who may be indicated for this test about biotin supplementation. Patients should be cautioned to stop biotin consumption at least 72 hours prior to the collection of a sample.

Expected Turnaround Time

Within 1 day

Specimen Requirements




0.8 mL

Minimum Volume

0.3 mL (Note: This volume does not allow for repeat testing.)


Red-top tube or gel-barrier tube.


If a red-top tube is used, transfer separated serum to a plastic transport tube.

Storage Instructions

Room temperature

Stability Requirements

Room Temperature Not recommended
Refrigerated 7 days
Frozen 4 weeks
Freeze/thaw/ cycles Stable x 3

Patient Information

To help diagnose thyroid disorders and to monitor treatment of hypothyroidism and hyperthyroidism; sometimes a TSH test is used to screen newborns for congenital hypothyroidism; there is no consensus within the medical community as to whether screening of adults should be done.

When you have signs and symptoms of hyperthyroidism or hypothyroidism and/or an enlarged thyroid (goiter) or when you have a thyroid nodule (a small lump on the thyroid gland that may be solid or a fluid-filled cyst); when you are being treated for a thyroid disorder.

A blood sample drawn from a vein in your arm or from pricking the heel of an infant.

No test preparation is needed. However, certain medications, multivitamins and supplements can interfere with the TSH test, so tell your healthcare practitioner about any prescribed or over-the-counter drugs and/or supplements that you are taking. If you take thyroid hormone as treatment for thyroid disease, it is recommended that your blood sample be drawn before you take your dose for that day. Acute illness may affect TSH test results. It is generally recommended that thyroid testing be avoided in hospitalized patients or deferred until after a person has recovered from an acute illness.