The development of a specimen exchange system for quality assessment of polymerase chain reaction tests

A programme of external quality assessment of polymerase chain reaction (PCR) assays through regular exchange of appropriate clinical or spiked specimens between Oxford and Cambridge public health laboratories began in February 1997. We report on 60 specimens included in the exchange. These covered most of the molecular diagnostic assays in use at present. In two cases discrepant results were obtained. We conclude that the exchange of specimens under code between laboratories that use molecular techniques as a diagnostic service is an inexpensive way of achieving regular external quality assessment.