Evaluation of the detection of the homologous transfusion of a red blood cell concentrate in vivo for antidoping

Homologous blood transfusion and doping: Where are we now?

Homologous blood transfusion (HBT) is used for doping in endurance sports since the 1960s. The blood comes from a compatible donor, that is, someone with a compatible ABO and rhesus blood group. Despite been prohibited by the IOC in 1985, no detection method was available until 2003. Then came the idea to use red blood cells (RBC) minor blood groups antigens that constitute an "identity" card of someone's RBC to detect the presence of a second RBC population. The method validated for doping control samples uses flow cytometry after incubation of isolated RBC with eight to 12 primary antibodies against specific minor blood groups antigens. The presence of double populations of RBC is revealed by a major and a minor peak in a fluorescence histogram. The sensitivity was estimated sufficient to detect HBT for a few weeks. Despite the complexity and cost of the method, right after its application in 2004, several cases of HBT were identified but the number of cases dropped rapidly over the years. In the 2010s, other ways to detect HBT were developed and evaluated: indirect detection using the Athlete Biological Passport approach, and a few years later forensic DNA analysis to establish the presence of two different DNA in a blood sample after HBT. Despite the high specificity of the latter, the sensitivity was recently questioned in vivo. Nowadays, the flow cytometry method remains the method of choice for HBT detection and recent investigations helped to simplify the method and increase its specificity and sensitivity.

A SNP-based genotyping strategy to detect the abuse of homologous blood transfusion from dried blood spots

We performed genotyping analysis of human biallelic polymorphisms (single nucleotide polymorphisms) for the detection of homologous blood transfusion in sports doping. DNA was extracted from dried blood spots and quantified real-time fast PCR. The method was proven to allow the detection of transfusions up to a donor percentage of 1%, with a significant improvement in terms of sensitivity with respect to both the reference cytofluorimetric method and a previously proposed strategy based on the DNA STR-based strategy.

Indirect biomarkers of blood doping: A systematic review

The detection of blood doping represents a current major issue in sports and an ongoing challenge for antidoping research. Initially focusing on direct detection methods to identify a banned substance or its metabolites, the antidoping effort has been progressively complemented by indirect approaches. The longitudinal and individual monitoring of specific biomarkers aims to identify nonphysiological variations that may be related to doping practices. From this perspective, the identification of markers sensitive to erythropoiesis alteration is key in the screening of blood doping. The current Athlete Biological Passport implemented since 2009 is composed of 14 variables (including two primary markers, i.e., hemoglobin concentration and OFF score) for the hematological module to be used for indirect detection of blood doping. Nevertheless, research has continually proposed and investigated new markers sensitive to an alteration of the erythropoietic cascade and specific to blood doping. If multiple early markers have been identified (at the transcriptomic level) or developed directly in a diagnostics' kit (at a proteomic level), other target variables at the end of the erythropoietic process (linked with the red blood cell functions) may strengthen the hematological module in the future. Therefore, this review aims to provide a global systematic overview of the biomarkers considered to date in the indirect investigation of blood doping.

Annual banned-substance review 16th edition-Analytical approaches in human sports drug testing 2022/2023

In this 16th edition of the annual banned-substance review on analytical approaches in human sports drug testing, literature on recent developments in this particular section of global anti-doping efforts that was published between October 2022 and September 2023 is summarized and discussed. Most recent additions to the continuously growing portfolio of doping control analytical approaches and investigations into analytical challenges in the context of adverse analytical findings are presented, taking into account existing as well as emerging challenges in anti-doping, with specific focus on substances and methods of doping recognized in the World Anti-Doping Agency's 2023 Prohibited List. As in previous years, focus is put particularly on new or enhanced analytical options in human doping controls, appreciating the exigence and core mission of anti-doping and, equally, the conflict arising from the opposingly trending extent of the athlete's exposome and the sensitivity of instruments nowadays commonly available in anti-doping laboratories.