GC-MS AS A REFERENCE METHOD IN IMMUNOCHEMICAL STEROID-HORMONE ANALYSES

The successful application of gas chromatography-mass spectrometry (GC-MS) as a reference method for the determination of steriod hormones in serum has been well-documented. We describe GC-MS reference methods for the determination of testosterone, progesterone, estradiol, and cortisol in serum. After addition of the labelled analog, extraction, HPLC-clean-up, and derivatization, the steroid hormone concentrations were determined by GC-MS. These concentrations were compared with the mean of the mean values reported by the different laboratories participating in the Wellcome Quality Control Program. The results indicate that mean values obtained with the respective immunoassays are usually positively biased in comparison with the GC-MS value.