MEASUREMENT OF FREE THYROXINE CONCENTRATION IN HUMAN SERUM*

Measurement of free thyroxine concentration in human serum.

In the present investigation the existence of "free" thyroxine in human serum was repeatedly verified by dialysis through cellophane, with paper chromatographic identification of thyroxine in the dialysate. Methods were developed for measurement of the minute amount of thyroxine present in the dialysate that was considered to represent the unbound or diffusible fraction of the hormone in serum....

Measurement of "free" thyroxine in serum.

A dialysis method for determining “free” thyroxine in diluted serum is presented. The effect of a number of variables (pH, incubation time and temperature, buffer composition and concentration, protein concentration, and specimen dilution) was studied, and pertinent data are presented. Withinrun precision (95% confidence limits) was ±10.6%; between-run precision was ±14.2%. Specimens from 84 he...

Association between serum free thyroxine concentration and atrial fibrillation.

BACKGROUND Previous studies have suggested that minor changes in thyroid function are associated with risk of atrial fibrillation (AF). Our objective was to determine the relationship between thyroid function and presence of atrial fibrillation (AF) in older subjects. METHODS A population-based study of 5860 subjects 65 years and older, which excluded those being treated for thyroid dysfuncti...

Free thyroxine in human serum: simplified measurement with the aid of magnesium precipitation.

The measurement of serum thyroxine in children.

A competitive protein-binding method was used to determine serum thyroxine concentration throughout childhood, adolescence, and in young adults. The values showed a gradual decrease as the child became older and reached adult levels by the time of adolescence. The range (mean +/- 2 SD mug/100 ml) for cord serum was 8.8-14.8; for 4 weeks to 11 years, 6.5-13.9; for 11 to 17 years, 5.4-12.2, and f...