Comparison of two time-resolved fluoroimmunoassays (TR-FIA), as applied to oestriol in human serum and progesterone in bovine milk.

We compared two time-resolved fluoroimmunoassay systems for measuring free oestriol in human serum and progesterone in bovine milk. By reading the fluorescence of europium complex of 4,7-bis(chlorosulphophenyl)-1,10-phenanthroline-2,9-dicarboxylic acid in solution, the measuring range is increased for both oestriol (10-50,000 ng/l instead of 25-50,000 ng/l) and for progesterone (10-50,000 ng/l instead of 25-10,000 ng/l). In addition, the interassay coefficients of variation were lowered from 9.5 to 5.7% for oestriol and from 7.5 to 5.4% for progesterone, at the smaller hormone concentrations detectable by each method.