Accuracy of a Direct Progesterone Immunoassay

Abstract

Immunoassay consistently overestimates serum progesterone levels so that low measurements (immunoassay <5 nmol/L) are too inaccurate to be used quantitatively. The utility of higher serum progesterone measurements by immunoassay and serum progesterone and other steroids measured by multiplex LC-MS profiling in predicting IVF pregnancy outcomes warrants further investigation. There is a need for caution in clinical diagnosis of premature luteinization based on increased late follicular phase serum progesterone measurements using direct progesterone immunoassay that consistently overestimates low serum progesterone concentrations.