A study on performance of two serological assays for diagnosis of leprosy patients

We compared 2 serological tests for the diagnosis of leprosy to test their performances. The tests include the serum antibody competition test (SACT) for the detection of antibodies to Mycobacterium leprae-specific epitope on 35 KDa protein molecule, and M. leprae gelatin particle agglutination assay (MLPA), for the detection of antiphenolic glycolipid-1 (PGL-1) antibodies. In both the assays a higher serological positivity was seen amongst multibacillary (MB) patients than those in paucibacillary (PB) patients. Taking all leprosy patients together, the sensitivity of SACT (59.7%) was observed to be statistically comparable to that of MLPA (66.9%). However, SACT proved to be more specific (97.7%) than MLPA (75.0%). The agreement between these 2 assays was observed to be moderate.