Accuracy of Two Progesterone Immunoassays for Monitoring In Vitro Fertilization

Background: Progesterone concentrations are routinely monitored during in vitro fertilization cycles. Immunoassay-based platforms are used most often in this setting because they are simple to use and amenable to same-day sample collection and result-reporting. However, immunoassay methods are subject to variation in specificity between different assay manufacturers. In this study, a set of unexpectedly high progesterone concentrations led to a method comparison between two in-house immunoassay platforms relative to the reference method. Methods: Progesterone was measured in 28 serum samples from women undergoing IVF cycles using the Siemens ADVIA Centaur Immunoassay system and the Abbott Architect i1000SR analyzer. A subset of these samples was selected for progesterone measurement by liquid chromatography–tandem mass spectrometry to define the accuracy of each immunoassay. Results: The Siemens ADVIA Centaur immunoassay system overestimated progesterone concentrations by 19% and the Abbott Architect overestimated progesterone concentrations by 5%. Conclusions: The Abbott Architect progesterone immunoassay provides a more accurate measurement of serum progesterone than the Centaur immunoassay at concentrations relevant for monitoring in vitro fertilization populations.