Normal free thyroxine in critical nonthyroidal illnesses measured by ultrafiltration of undiluted serum and equilibrium dialysis. J Clin Endocrinol Metab 1988;67:1031-9.
Ultrafiltration Immunoassays Retentate Ultrafiltrate Total [T.sub.4], nmol/L 139 ND Analog free [T.sub.4], pmol/L 34.7 ND Nonanalog free [T.sub.4], pmol/L 129 20.6 Equilibrium dialysis Immunoassays Retentate Dialysate Total [T.sub.4], nmol/L 77 ND Analog free [T.sub.4], pmol/L 17 ND Nonanalog free [T.sub.4], pmol/L 129 19 ND, not detected: total [T.sub.4] <12.87 nmol/L or free [T.sub.4] <1.29 pmol/L.
Artifactually elevated serum-free thyroxine levels measured by equilibrium dialysis
in a pregnant woman with familial dysalbuminemic hyperthyroxinemia.
A simple and rapid method to measure non-protein-bound fractions of cortisol, testosterone and oestradiol by equilibrium dialysis: comparison with centrifugal filtration.
A simplified method for the calculation of unbound or free testosterone by equilibrium dialysis of undiluted plasma.
Some limitations of using equilibrium dialysis to study human serum albumin-testosterone interaction.
(5) Nonstandard abbreviafions: FTe and TTe, free and total testosterone, respectively; SHBG, sex-hormone-binding globulin; (i)ED, (indirect) equilibrium dialysis; UF, ultrafiltration; SyD, symmetric dialysis; RMP, reference measurement procedure; ID-GC/MS, isotope dilution-gas chromatography-mass spectrometry; SIM, selected-ion monitoring; and IQC, internal quality control.
Higher F[T.sub.4] concentrations have been found by the ultrafiltration technique than by equilibrium dialysis; consequently, no consensus has yet been achieved concerning the F[T.sub.4] content in human serum (2, 11, 12).
Equilibrium dialysis was performed using an assay from Nichols Institute Diagnostics.
Therefore, the authors concluded that electrolyte and pH disturbances affect measurements of F[T.sub.4] concentrations in serum by an equilibrium dialysis method to only a minor extent (15).
Equilibrium dialysis seems the least compromised method.
Ultrafiltration devices tested for use in a free thyroxine assay validated by comparison with equilibrium dialysis. Scand J Clin Lab Invest 1990;50:663-9.