Elevated serum free thyroxine by thyroxine analog radioimmunoassays in euthyroid patients with familial dysalbuminemic hyperthyroxinemia

Journal Article · Wed Dec 01 04:00:00 EST 1982 · Ann. Intern. Med.; (United States)

DOI:https://doi.org/10.7326/0003-4819-97-6-865· OSTI ID:5997015

Rajatanavin, R; Fournier, L; DeCosimo, D; Abreau, C; Braverman, L E

A study was done to ascertain whether the serum free T4 measured by free T4 radioimmunoassay kits would, like equilibrium dialysis, be normal in patients with familial dysalbuminemic hyperthyroxinemia. Five free T4 radioimmunoassay kits were used to measure free T4 in serum samples from 19 patients with familial dysalbuminemic hyperthyroxinemia and 20 healthy volunteers. Values (mean +/- SE) for T4, free T4 index, and free T4 (equilibrium dialysis) in these normal subjects and patients with familial dysalbuminemic hyperthyroxinemia, respectively, were as follows: T4, 8.1 +/- 0.2 and 18.3 +/- 0.7 ..mu..g/dL; free T4 index, 3.1 +/- 0.1 and 7.3 +/- 0.3 ..mu..g/dL; free T4, 1.4 +/- 0.1 and 1.2 +/- 0.1 ng/dL. The following free T4 radioimmunoassay methods were used: antibody coated microfine silica, microencapsulated antibody, two-step antibody-coated tube, and one-step /sup 125/I-T4 analog (2 kits). The present findings in patients with familial dysalbuminemic hyperthyroxinemia and previous observations in ill euthyroid patients suggest that serum free T4 measured by some radioimmunoassay methods must be interpreted with caution in these two clinical situations. (JMT)

• Research Organization: Univ. of Massachusetts Medical School, Worcester
• OSTI ID: 5997015
• Journal Information: Ann. Intern. Med.; (United States), Journal Name: Ann. Intern. Med.; (United States) Vol. 97:6; ISSN AIMEA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
AMINO ACIDS
BETA DECAY RADIOISOTOPES
CARBOXYLIC ACIDS
COMPARATIVE EVALUATIONS
DAYS LIVING RADIOISOTOPES
DISEASES
ELECTRON CAPTURE RADIOISOTOPES
HALOGEN COMPOUNDS
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE COMPOUNDS
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MEASURING METHODS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC IODINE COMPOUNDS
PATIENTS
PEPTIDE HORMONES
RADIOASSAY
RADIOIMMUNOASSAY
RADIOISOTOPES
THYROID HORMONES
THYROXINE
TRACER TECHNIQUES