Evaluation of dual-label simultaneous assays for lutropin and follitropin in serum.

We evaluated the analytical performance and clinical utility of three dual-label simultaneous assays for lutropin and follitropin by comparison with widely used individual assays for these analytes (Diagnostic Products Corp.; DPC). Of the three assays evaluated, "Cotropin" (Clinetics Corp.) and "Combostat" (Micromedics Systems, Inc.) compared favorably with the DPC assay with respect to recovery, linearity, intra- and inter-assay precision, and sensitivity for lutropin. The third assay evaluated, "Simultropin" (Becton Dickinson Immunodiagnostics), exhibited greater interassay variability for lutropin than did the DPC assay but otherwise compared favorably. Analytically the three assays were similar to one another for follitropin determinations and results compared favorably with those by the DPC assay. Intercorrelation of patients' results obtained with these assays is poor. However, using the same standards with each of the three assays improved intercorrelation of patients' data except for follitropin by Combostat. A universally accepted reference material for immunoassay of lutropin and follitropin is needed.