Comparison of newly developed immuno-MS method with existing DELFIA immunoassay for human chorionic gonadotropin determination in doping analysis

Background: The performance of a method for MS determination of human chorionic gonadotropin (hCG) was compared with a reference method currently used in World Anti-Doping Agency accredited doping laboratories – the DELFIA® immunoassay. Results: A strong correlation was demonstrated for the serum samples. However, for the urine samples, DELFIA reported significantly lower quantitative hCG measurements than the MS method. This was explained by the relatively unstable content of intact hCG-heterodimer in urine during storage compared with in serum. Discrepancies observed for the urine analyses might be related to the molecular dissociation of intact hCG-heterodimer into free subunits during storage, and...