Accredited laboratories are requested to participate to the WADA Quality Assurance system. For that purpose WADA distributes blind and double blind samples (see flaw#1) having either a known nominal value or a consensus value. The preparation of such samples needs great attention as it may effect the homogeneity of the blood or urine sample and therefore the nominal value.
A concern is that WADA does not specify how a consensus value is obtained in case that the nominal value of a threshold substance is unknown. It is common practice to invite several expert laboratories to quantify the threshold substance in a urine or blood sample using their method of choice. The consensus value is then the mean of the results reported by these laboratories. However because the reported results will vary, an uncertainty should be associated to this consensus value. There is, however, a complication that extreme or outlying values may be found. Therefore WADA should have procedures implemented for detecting and/or removing outlying results when calculating the consensus value. It is generally known that outliers should be removed with extreme care as it may render the uncertainty unrealistically low. However WADA ISL 2009 does not consider this uncertainty at all in their calculation of the laboratory score. Moreover these uncertainties are not available to athletes defenders.