Periodic Graphics: The Russian doping scandal

They should check for DNA in urine. If it is not the athlete's DNA or is a mixture, then switching is possible. A mixture can occur by substituting saliva from the athlete + another's urine. However, looking at the types of cells helps uncover this cheating as well. This is an easy and cheap test as the laboratory already has the blood so has the DNA for RFLP testing (or DQ-alpha).

Thanks for the update. I was just commenting that one could have applied these techniques to urine to identify the individual providing the sample even in the early 1990s. One need not have specific identification only that the sample under question was not consistent with individual A. We did use DQ-alpha at the time and if I remember correctly it is about 93% discriminatory (i.e about 1 in 20 random individuals have the same phenotype). We were one of the first to DNA type urine (frozen, old samples) but did not implement it because one can cheat the test. Therefore, I lost interest. Are the cheating techniques known or were they known a decade ago and thus could they been applied to these historic samples to beat the urine test? Although I alluded to it, should these cheating techniques be discussed on this forum?