|The World Anti-Doping Program is based on the perceived deterrence model, in which the choice to refrain from using prohibited substances is driven by the potential that the athlete could be tested, that the test could detect the doping substance, and that the penalty for being caught is significant. Thus, the inability of analytical methodology to detect abuse would significantly weaken the deterrent effect. From a historical perspective, chromatography coupled to mass spectrometry has always been the backbone of anti-doping testing. The first major advance in curtailing steroid use, for example, came at the 1983 Pan American Games with the introduction of sensitive benchtop GC-quadrupole MS testing.|
The World Anti-Doping Agency Prohibited List details ten classes of compounds and two sets of methods that are forbidden out-of- and/or in-competition. Synthetic compounds are prohibited at any concentration at which they can be identified, although guidance on laboratory performance is provided through a series of WADA Technical Documents (www.wada-ama.org). Detection of one or more metabolites in the urine supports the laboratory finding of an adverse analytical finding. Both GC-MS and LC-MS-MS detection methods have been incorporated into testing.
The detection of substances that occur naturally in the body (e.g., testosterone, growth hormone) presents a challenge. It is well known that most substances appearing in the urine vary widely in concentration, so measurement of concentration is not a reasonable approach. The first means of detecting the use of testosterone was achieved by measuring the testosterone-to-epitestosterone ratio (T/E ratio). Initially the T/E ratio was compared to population reference ranges, but more recently intra-individual reference range assessment methods such as the reference change and “predictive” models have been used. Gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) has also been used to identify non-physiological source of testosterone and its precursors. Recently fast GC-C-IRMS and GCxGC-C-IRMS have been developed for steroid analysis.
In the past decade, blood has become the matrix of choice for detection of blood doping and peptide/protein hormones. Both direct detection of hormones and their isoforms and the detection of biomarkers are being employed to assess abuse of recombinant hormones. Mass spectrometry will play a significant role in peptide/protein detection and identification. The use of stable-isotope labeled internal standards will provide the opportunity to develop methods with improved measurement uncertainty.
The field of anti-doping science requires an appreciation of clinical, forensic, and analytical science.