TSH (Thyroid Stimulating Hormone)

What is a TSH test?

• Measures the level of Thyroid‑Stimulating Hormone (TSH) in the blood.
• TSH is produced by the pituitary gland and regulates the thyroid gland’s production of thyroid hormones (T4 and T3).

Key parameters

Why it is done

• Routine health check‑up or annual screening.
• Evaluation of symptoms such as fatigue, weight changes, cold intolerance, or menstrual irregularities.
• Monitoring of thyroid disorders (hypothyroidism, hyperthyroidism) or treatment response.

Early detection

The test can help identify signs of thyroid dysfunction, but it does not diagnose a disease on its own. A doctor interprets the result together with symptoms, history, and other tests.

What abnormal results may mean

• High TSH: Often suggests an underactive thyroid (hypothyroidism) or pituitary dysfunction.
• Low TSH: May indicate an overactive thyroid (hyperthyroidism) or excess thyroid hormone therapy.
• Many factors—medications (e.g., amiodarone, steroids), pregnancy, recent illness, or lab variability—can affect levels.

Who might be advised to get this test

• Adults with symptoms of thyroid imbalance.
• Pregnant women or those planning pregnancy.
• Individuals on thyroid medication needing dose adjustment.
• People with a family history of thyroid disease.

In short: A TSH test measures pituitary‑thyroid signaling and helps screen for thyroid disorders, guiding further evaluation and management.

• Fasting: No fasting required.
• If combined with fasting tests: Follow the longest fasting requirement among all tests.
• Procedure: A healthcare professional draws a small amount of blood (usually 5–10 mL) from a vein in the arm using a needle. The process takes about 5 minutes.
• Discomfort: A brief pinch or sting from the needle; the site may feel sore for a few minutes.
• Precautions: No special medication timing needed for TSH. Avoid heavy alcohol or intense exercise 24 hours before the test if you are also undergoing other tests that require such precautions.
• Note: Confirm any specific preparation with your doctor or the lab. This information is general educational content and not a substitute for professional medical advice.