title: Is there a place for the estimation of free tri-iodothyronine levels in the diagnosis of hypothyroidism?
abstract: In this study free thyroxine (fT4) and free tri-iodothyronine (fT3) levels were assayed in 87 patients with a clinical diagnosis of hypothyroidism who had elevated thyrotrophin (TSH) levels (greater than 5.5 mU/l). fT4 levels were decreased in 72 of these 87 patients. However, only 44 of the 72 patients with low fT4 levels and increased TSH levels had a decreased concentration of fT3. The remaining 28 patients had normal fT3 levels. It appears that fT3 levels have little, if any, place in screening for hypothyroidism.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D012015:Reference Standards; D013974:Thyroxine / Q000097:blood*; D014284:Triiodothyronine / Q000097:blood*
chemical_list: D014284:Triiodothyronine; D013974:Thyroxine