CLASSIFICATION OF LEPROSY CASES UNDER FIELD CONDITIONS IN BANGLADESH .2. RELIABILITY OF CLINICAL-CRITERIA

In 2 non-governmental organization projects 244 new leprosy patients i n Bangladesh were classified in the field according to clinical criter ia i.e. number of skin lesions and number of enlarged nerves. Comparis on of these classification results with the results of skin smears and biopsies yielded a sensitivity (for detection of a MB case) of 92.1%, but the 'unconfirmed MB rate' amounted to 52.6%. In order to improve the reliability of the operational classification, several additional clinical criteria were investigated. It was found that neither the pre sence of anaesthesia in the skin lesions nor the presence of grade 2 d isabilities or peripheral anaesthesia or voluntary muscle testing (VMT ) impairment contributed to an improved classification. Counting the n umber of body areas showing signs of leprosy, which had proven very us eful in other programmes, did not result in a more reliable classifica tion in the 2 projects in Bangladesh. The presence of clinical signs o f lepromatous leprosy, more specifically nodules or diffuse infiltrati on, could be a useful addition to the classification criteria. If the sensitivity must remain higher than 90%, the lowest 'unconfirmed MB ra te' obtainable in Bangladesh, using clinical criteria only, is 46.4%, for a sensitivity of 91.0%. However, the inclusion of skin-smear resul ts in the classification criteria could improve the sensitivity to 96. 6% and lower the 'unconfirmed MB rate' to 40.3%. A reduction in MB ove rclassification will result in more efficient and more cost-effective leprosy control programmes.