Classification of leprosy cases under field conditions in Bangladesh. I. Usefulness of skin-smear examinations.

In 2 non-governmental organization projects in Bangladesh 244 new leprosy patients were classified in the field according to clinical criteria. Skin smears were taken at 4 standardized sites and at the most active peripheral lesion, where a biopsy was also taken. Comparison of the clinical field classification with the results of the skin smears and biopsies gives a sensitivity of 92.1% for the clinical criteria, but a specificity of only 41.3%. The skin-smear results, on the other hand, have a sensitivity of 88.4% and a specificity of 98.1%. Thus, skin smears may contribute considerably to the operational classification of leprosy patients under field conditions. Quality control of the peripheral laboratory is essential. Appropriate site selection for the smear taking will also contribute to increased performance. Analysis of the skin-smear results suggests that the policy of taking smears at standardized sites should be abandoned in favour of the earlobes and active peripheral lesions.