A study suggesting that a single urine sample is unable to correctly determine a dosage level of salbutamol it seems that will form a key part of Chris Froome’s defence.
The report published in the British Journal of Clinical Pharmacology claims it is not feasible to determine a dosage level of salbutamol based on the results of a single “untimed” urine sample.
Under WADA rules, salbutamol use has a maximum dosage threshold of 1600 micrograms over 24 hours in divided doses, and 800 micrograms over 12 hours.
However, the new study draws on previous research to build a stimulation model. It is based on WADA’s 12 hour limit and while studies into adult humans were used, the authors also drew on literature using dogs.
Froome’s failed test recorded a level of salbutamol at 2,000ng/ml, double the amount permitted by the World Anti-Doping Agency. Under new WADA rules there is an allowance made for specific gravity, in effect to take into account of possible dehydration and urine concentration. It is understood Froome’s reading has been recalibrated to 1,429ng/ml, which is still an adverse analytical finding and could lead to an anti-doping rule violation.
The research claims on a maximum dosage of salbutamol, as many as 15.4 per cent of tests could return a false positive. It states: “the current threshold inadvertently leads to incorrect assumptions of violation, whereas many violations will go unnoticed,” and says that the testing should be reconsidered.