Issues in detecting abuse of xenobiotic anabolic steroids and testosterone by analysis of athletes' urine. Catlin DH, Hatton CK, and Starcevic SH. Clin Chem. 1997 43(7):1280-8.
"For the extremely rare athlete with a naturally increased T/E ratio, the T/E remains chronically increased." Article also mentions that hormones in meat products can and do cause abnormal short duration spike test readings in nonusers.
If the officials are clever (or someone in their camp actually uses PubMed):
Bayesian detection of abnormal values in longitudinal biomarkers with an application to T/E ratio. Sottas PE, Baume N, Saudan C, Schweizer C, Kamber M, and Saugy M. Swiss Laboratory for Doping Analyses, Universite de Lausanne, 1066 Lausanne, Switzerland. Biostatistics. 2006 Jun 19.
We developed a test that compares sequential measurements of a biomarker against previous readings performed on the same individual. A probability mass function expresses prior information on inter-individual variations of intra-individual parameters. Then, the model progressively integrates new readings to more accurately quantify the characteristics of the individual. This Bayesian framework generalizes the two main approaches currently used in forensic toxicology for the detection of abnormal values of a biomarker. The specificity is independent of the number n of previous test results, with a model that gradually evolves from population-derived limits when n=0 to individual-based cut-off thresholds when n is large. We applied this model to detect abnormal values in an athlete's steroid profile characterized by the testosterone over epitestosterone (T/E) marker. A cross-validation procedure was used for the estimation of prior densities as well as model validation. The heightened sensitivity/specificity relation obtained on a large dataset shows that longitudinal monitoring of an athlete's steroid profile may be used efficiently to detect the abuse of testosterone and its precursors in sports. Mild assumptions make the model interesting for other areas of forensic toxicology.
Can't say more about this issue one way or the other, without seeing the data and cause history. Maybe the Swiss authors of that very recent biostat article will contact the officials Tour D France officials, or maybe they already have and are, at this moment, busily crunching numbers, knowing that this high profile case will be good for their grant futures. (wry comment on my part).
Cheers.
PS: I supplied you with a fuck of a better answer (and citations) than JB did. He should learn his analytical chemistry a bit better.
http://www.johnberardi.com/
