Buruli ulcer laboratory network and new external quality assessment programme for PCR-based diagnosis in the WHO African Region. Terms of reference

A total of 18 laboratories from 13 countries participated in the four rounds of EQA: 10 laboratories from eight African endemic countries, four of which participated in all four rounds and three in three rounds. The overall results showed that the median performance of these laboratories improved over the four rounds. However, the proportion of laboratories reporting false–positive cases remains high and indicates a problem of specificity probably due to contamination. The proportion of laboratories reporting both false–positive and false–negative results raises the issue of the quality of the data reported by WHO in Africa as well as the results of the studies carried out in these different laboratories in various countries.