Serum tumour markers: from quality control to total quality management

Since the first clinical use of tumour markers, quality assurance has been considered only in a restrictive manner, that is, as a surveillance of the analytical process. In other words, quality assessment was roughly viewed a s a synonymous with quality control. This is not surprising, since tumour m arkers are almost exclusively assayed by radioimmunoassays, whose analytica l performance were suboptimal in the 1970s. Furthermore, tumour marker conc entrations in biological fluids were very low (in the ng range); in additio n, primary standards were not available and dose-response curves were set u p with conventional calibrators. Therefore, quality control programmes have become mandatory to restrict intra-and inter-laboratory variability. (C) 2 000 Harcourt Publishers Ltd.