Triiodothyronine (T3), Free

Testing:  Fasting: no requirement Fasting is not required for this test. Take all medications as prescribed. If you are supplementing with any hormones, we suggest taking them approximately 2 hours prior to having your blood drawn to see peak levels. Hormones are best drawn between 8-10 AM. Hormonal contraceptives can interfere with progesterone and estrogen results. Pre-menopausal women: For a 28 day cycle, blood should be drawn on day 21 (day 1 is the day that bleeding begins). For longer or shorter cycles, count 8 days back from the day your next menstruation would start. Post-menopausal women: Blood can be drawn any day of the month. Specimen: Blood