Some realities and results of proficiency testing of laboratories performing toxicological analyses

The results of proficiency testing and performance monitoring of laboratories that undertake the identification and quantitation of drugs present in physiological specimens on a fee-for-service basis are examined. In spite of an accompanying history strongly suggesting the presence of one or more specific compounds in a given specimen, a surprising number of laboratories failed in the identification of the compound or false identification was encountered. Similarly, a disappointing number of the reported quantitative results were outside an arbitrarily assumed acceptable range of 85 to 115% of the various target (putative) values. The results reported by referee laboratories were also less uniform than expected. Considering the charges made to customers for such analyses, it is reasonable to expect a better quality of performance. Some comments on the possible means of achieving this will be made.