RESUMEN
Objective:To establish a candidate reference method for serum progesterone using isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS) in our laboratory, validate the analytic performance of five clinical routine detection systems to explore the comparability of serum progesterone detection by different detection systems.Methods:A candidate reference method for serum progesterone using ID-LC/MS/MS method was established. The sample was pretreated by liquid-liquid extraction method, and the reversed phase liquid phase separation in positive ion mass spectrometry mode was used to detect progesterone in human serum, and the detection time of a single sample was controlled within 5 minutes by gradient elution. In order to improve the accuracy of the method, the bracketing calibration method (BCM) was used to establish the standard curve. The sensitivity, accuracy, precision and specificity of BCM and classical calibration curve method were evaluated according to CLSI C62-A, EP15-A2, EP6-A2 and EP9-A3, and the analytical performance and comparability of five clinical routine progesterone detection systems were evaluated,compared with ID-LC/MS/MS method, the bias at medical decision level 2 and 25 ng/ml was evaluated to see if they were <1/2TEa (12.5%).Results:The limit of detection (LOD) of ID-LC/MS/MS was 0.005 ng/ml. The recoveries of BCM method and classical calibration curve method are 97.95%-101.58% and 96.88%-110.70%, respectively. The measurement results of BCM method for certified reference materials are within its declared uncertainty range. The intra-and inter-assay coefficient of variation ( CV) of BCM method was less than 3.0%, which was better than that of classical calibration curve method ( CV: 2.48%-9.33%). The precision and linear range of the five clinical routine detection systems can meet the detection requirements. The measurement bias of detection system 1, 3 and 5 at 25 ng/ml of medical decision level was less than 1/2TEa, and the measurement bias at 2 ng/ml of medical decision level was more than 1/2TEa. The measurement bias of detection system 2 and 4 at two medical decision levels was less than 1/2TEa. Conclusion:The candidate reference method for serum progesterone ID-LC/MS/MS established in our laboratory meets the requirements of the reference method. BCM has better detection performance than classical calibration curve method. The precision and linearity of the five progesterone clinical detection systems are satisfactory. The five clinical detection systems could meet the clinical requirements at the medical determination level of 25 ng/ml, however, only two of the five clinical detection systems meet the clinical requirements at the medical determination level of 2 ng/ml.