A multi-parametric approach to remove the influence of plasma volume on the ABP during a UCI cycling stage race

Code: ISF18D10LL

Fluctuations in plasma volume present a major confounding factor to the analysis of an Athlete's Biological Passport (ABP) profile.  A recently developed model for plasma volume estimation via a simple blood test will be applied to samples collected during a cycling stage race. The model will be used to correct the concentration based hematological markers of the ABP, in order to account for the natural progressive plasma volume expansion induced by the multi day stage racing. The proposed research serves to validate the model in an anti doping context, which if successful presents an exciting step forward for the ABP and anti doping authorities.

Main findings: 

Fluctuations in plasma volume (PV) present potential confounders within the concentration-based markers of the hematological Athlete Biological Passport (ABP). Here, a multi-parametric approach involving a simple blood test is applied to the current ABP adaptive model in an attempt to remove the influence of PV expansion, induced by a cycling stage race. Blood samples were obtained from 29 professional cyclists (15 female, 14 male) before, during, and after consecutive days of cycle racing (Tour Down Under, Adelaide, South Australia). Whole blood was analyzed in accordance with the World Anti-Doping Agency (WADA) ABP guidelines at the WADA Accredited Laboratory in Sydney (ASDTL). Serum and plasma were analyzed for hemoglobin concentration ([Hb]), platelets, transferring, albumin, calcium, creatinine, total protein, and low-density lipoprotein. Significant reductions in [Hb] and the OFF-score were observed in female cyclists after 3 and 4 days of racing, with accompanying increases in PV, which returned to baseline values 4 days post competition. Similarly, a significant increase in PV was observed in male cyclists after 3 and 5 days of racing. PV was calculated using the CO-rebreathing method. When individual calculations of PV were applied to the adaptive model, the upper and lower reference predictions of [Hb] and the OFF-score were refined such that all outliers consistent with racing induced PV changes were removed. The multi-parametric PV model appears capable of reducing the influence of PV on volumetric markers during competition. This is an important step towards the inclusion of the PV correction in the hematological module of the ABP. Future work should consider intra laboratory and intra analyzer variation as well as adquirig more longitudinal data on elite athletes from different disciplines.