Determining the Compliance of the Sysmex XR‐1000 Haematology Analyser With WADA Athlete Biological Passport Specifications

The athlete biological passport (ABP) has been established as an anti-doping tool based on the statistical analyses of an athlete's biological variables over a period of time. It was introduced in 2007. An important aspect to ensure interlaboratory comparability was to use only one analytical platform-the Sysmex XT-2000. When the new Sysmex XN-1000 platform replaced the XT-2000i in 2019, there was a bias for the reticulocyte percentage. Although clinically insignificant, it interfered with interpreting athletes' haematological profiles for anti-doping purposes; therefore, it was necessary to adjust the haematological module. With the introduction of the new Sysmex XR-Series in 2023, an implementation of this new instrument could become necessary in the future. While the analytical performance of the XR-Series for clinical purposes has been evaluated previously, data in the context of ABP requirements, which are defined in WADA's technical documents, are not available. Therefore, our goals were to compare the XR-series with the XN-1000 and to evaluate their performance within an anti-doping context. Over 300 samples were analysed on the two instruments following WADA's technical document TD2021BAR, which defines the analytical requirements. The results for all ABP parameters including the calculated OFF-Score (OFF-hr) and the Abnormal Blood Profile Score (APBS) showed excellent interplatform comparability. In conclusion, our study demonstrates that the Sysmex XR meets WADA's requirements for haematological analysis. It can confidently replace the Sysmex XN in anti-doping laboratories without compromising the integrity of WADA's ABP longitudinal profiles.