Abstract
The results from an external quality control scheme for the assay of paracetamol in serum are reported. A preferential method of assay has not become evident, but, as a result of the scheme, some laboratories have changed or modified their techniques or have re-established the limits of detection. The majority of laboratories were able to estimate paracetamol satisfactorily at those levels which are of clinical importance. The overall group performance has shown little change. The programme has had considerable impact in so far as it has led to a mutually useful interchange of information and trouble shooting.