What is the best test for monitoring levothyroxine therapy?
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013960:Thyroid Function Tests; D013974:Thyroxine / Q000097:blood / Q000627:therapeutic use*; D014284:Triiodothyronine / Q000097:blood
D014284:Triiodothyronine; D013974:Thyroxine