Fast, sensitive, and reliable

Abstract

For several decades the use of prohibited methods and substances in sport has been controlled by doping testing. Harmonization of the global anti-doping activities and rules, as well as the guarantee of legal protection of the athlete are just some examples of the tasks of the World Anti-Doping Agency (WADA) in order to promote, coordinate, and monitor the fight against doping in sport. A well-planned testing strategy for anti-doping organizations is a key element in order to obtain representative samples and a correct biomatrix for efficient doping control, but the contribution of anti-doping laboratories is also fundamental to the overall success. Analytical methods may be needed to reveal potential masking attempts and fraud which could take place outside the sample collection session (e.g. haemodilution) to complement carefully supervised sample collection procedures. As pre-analytical processes, laboratories verify the authorized origin, evaluate the transport time and conditions, and also verify the identity and integrity of the biological samples at the time of receipt. In the actual analytical processes, fit-for purpose methods and instrumentation are used for the detection of prohibited substances which are specified by WADA.1 The majority of the prohibited substances are exogenous, i.e. they are not naturally present in the body. In these cases, qualitative identification of the substance and/or its metabolite is sufficient for establishing an anti-doping rule violation. In the prohibited list, however, there are substances such as testosterone, erythropoietin (EPO), growth hormone (GH), and insulin-like growth factor 1 (IGF-1), which are available as pharmaceutical products for clinical purposes, but which are also produced endogenously. In these cases the analytical methods and result interpretation should be capable of discriminating between exogenous source and clinical or pathological conditions. Implementation of gas chromatography-combustion-isotope ration mass spectrometry (GC-C-IRMS) has enabled the analysis of endogenous anabolic steroids and their misuse, whereas methods based on electrophoretic techniques (IEF-PAGE and SDS-PAGE) and immunoassays have provided tools to detect large biomolecules, the concentration of which is still often below the sensitivity limits of mass spectrometric approaches. Research projects within these special topics require active and devoted scientists, and also provide significant improvements for routine analysis in the form of enhanced detection times and by facilitating the result evaluation.2-5 In general terms, technical improvements, for example enhanced chromatographic and mass spectrometric resolution, higher sensitivity, scan-to-scan polarity switching, and more powerful data analysis allow for faster, more sensitive, and more reliable screening strategies. According to the prevailing International Standard for Laboratories (ISL), the doping control samples can be re-analyzed within a time period of up to eight years following the reporting of the original result.6 This is particularly interesting when new instrument technologies are introduced in the analysis routine for the purpose of monitoring new drug-derivatives or new chemical entities emerging onto market,7 and also when new long-term excreted metabolites are reported for already known prohibited substances.8Although the flexibility of the ISL increases the risk of an adverse analytical finding, it also requires adequate sample storage condition and knowledge on the long-term effects on various analytes. The list of prohibited substances is updated annually; active research and up-to-date analytical processes are mandatory in order to reveal the high-risk emerging compounds and to target the appropriate sample matrix. The laboratories' assignment is to search for and to adapt the applicable parts of modern methodologies to the anti-doping context. In the success of these research projects and with efficient implementation of new techniques, international and interdisciplinary co-operation plays a major role. Similar to any branch of applied sciences, in doping control the science is not for science's sake only. With respect to routine analysis and service to the customers, these improvements should be also practical, prompt, flexible, and cost-effective. This special issue of Drug Testing and Analysis summarizes a fine selection of contributions from international research projects of anti-doping laboratories from the 31st Cologne Workshop on Dope Analysis – all present recent advances in sports drug testing and progress in the fight against doping in sport.