FreeT3

This laboratory investigation measures FreeT3, which may help assess endocrine function, reproductive health, or another hormone-related clinical question. Hormone concentrations can vary with time of day, menstrual-cycle phase, pregnancy, age, medicines, and the reason for testing. The ordering clinician may therefore specify a particular collection time or cycle day. Results should be interpreted with symptoms, medical history, and related investigations rather than used alone to make a diagnosis. Follow the laboratory’s specimen and preparation instructions before collection.