Serological diagnosis of HIV infection: practice and performance in western Europe

Current laboratory practice in testing for HIV antibodies in western Europe was investigated by means of a questionnaire addressed to the 12 EC countries and Finland, Norway, Sweden and Switzerland. Despite inevitable regional differences there was a fair degree of homogeneity in broad laboratory organisation and in the types of tests and confirmatory strategies used. The primary test is always some form of enzyme linked immunosorbent assay (ELISA), though a number of laboratories also use agglutination tests. Confirmation is by an ELISA of a different type, or by Western blot, or both. The size and workload of laboratories covered a wide range. It is suggested that laboratories doing only a small number of tests at infrequent intervals should take extra care in validating their results and should be closely monitored. Twelve of the 16 countries studied have a quality assurance scheme for monitoring laboratory performance. Participation is voluntary but is invaluable even for the largest laboratories. The results suggest that the standard of laboratory diagnosis is reasonably uniform throughout the region, which is not only important for the individual patient but means that epidemiological comparisons of data from different areas have at least a sound technical base.