was ist ft3 — what does this mean exactly?

FT3 stands for free triiodothyronine, the biologically active form of the thyroid hormone T3. It is measured in blood and reflects current thyroid function. Unlike total T3, FT3 is not bound to transport proteins and can act directly on cells. Normal FT3 levels typically range from about 2.0 to 4.4 pg/mL depending on the lab. Elevated levels may indicate hyperthyroidism, while low levels can suggest hypothyroidism or non-thyroidal illness (euthyroid sick syndrome). FT3 alone is not diagnostic; it is usually interpreted together with TSH and fT4. In consumer lab tests (e.g., MyBody-X), FT3 is often included as part of a hormone panel. The measurement is technically reliable, but interpretation should always be done by a physician, as many factors (time of day, medications, diet) affect values. The evidence for the clinical relevance of FT3 is strong (human-strong), but viewing it in isolation without medical context can be misleading. Caveat: self-tests do not replace medical diagnosis.