Sensitivity and specificity of methods of classification of leprosy without use of skin-smear examination

The classification of leprosy is closely linked to chemotherapy as seen in the premultidrug therapy (MDT) era, when the Ridley-Jopling system ((9)) wa s used to determine the duration of dapsone therapy. The introduction of MD T in 1982 included a revised and simplified classification into two groups, multibacillary (MB) and paucibacillary (PB) ((16)). MB was classified usin g skin-smear results when the bacterial index (BI) was greater than or equa l to 2+, This was revised by the World Health Organization (WHO) Ex pert co mmittee in 1988 ((13)) so that the finding of a positive smear at any site led to MB classification. In 1993 the WHO Study Group suggested that clinic al methods alone could be used for classification where facilities for skin smears were unavailable or unreliable ((15)).