Report of the IFCC Working Group for Standardization of Thyroid Function Tests; part 2: Free thyroxine and free triiodothyronine
Chopra IJ: Simultaneous measurement of free thyroxine and free 3,5,3- triiodothyronine in undiluted serum by direct equilibrium dialysis/radioimmunoassay: evidence that free triiodothyronine
and free thyroxine are normal in many patients with the low triiodothyronine syndrome.
Hormonal research revealed a severely decreased thyrotropin level, whereas total and free triiodothyronine
and thyroxine levels were normal.
Coronary flow rates of all patients and control subjects were documented by Thrombolysis In Myocardial Infarction (TIMI) frame count, serum level of Hs-CRR NT proBNP sedimentation, leukocyte, free triiodothyronine
(FT3), free thyroxine (FT4), thyroid stimulating hormone (TSH) and fibrinogen levels were measured.
11] The tests covered by this group are total thyroxine (TT4), total triiodothyronine (TT3), free thyroxine (FT4), free triiodothyronine
(FT3), and thyroid-stimulating hormone (TSH).
The analytical validity and standardization of free thyroxine (FT4) and free triiodothyronine
(FT3) testing, however, has been a matter of ongoing debate (6-16).
After an overnight fast, blood samples were collected from all the study subjects for determination of serum TSH, free triiodothyronine
Report of the IFCC Working Group for Standardization of Thyroid Function; part 2: free thyroxine and free triiodothyronine
Thyroid function tests confirmed hyperthyroidism with a serum free triiodothyronine
(FT3) level of 13,4 pg/ml (1,7-4,9), serum free thyroxin (FT4) level of 5,4 ng/dl (0,7-2,0) and thyrotropine (TSH) level of <0.
We have read with interest recent reports of the measurement of free thyroxine and free triiodothyronine
by ultrafiltration and tandem mass spectrometry (1-4).