How to prepare for TSH Test

For a TSH (thyroid-stimulating hormone) test, no special preparation is usually required. However, several factors can affect results. High-dose biotin (≥10 mg/day) can falsely lower TSH; stop biotin supplements 2–3 days before testing. TSH follows a circadian rhythm (peak at night, nadir in afternoon); for consistent comparison, blood draw should ideally be done in the morning, fasting. If you take thyroid medication (e.g., levothyroxine), continue as usual unless your doctor advises otherwise. MyBody-X tests are screening tools, not diagnostic. An abnormal result should be confirmed by a physician. Caveat: single measurements can fluctuate; repeat testing may be needed for borderline values.