Evaluation of Direct Agglutination Test, rk39 Test, and ELISA for the Diagnosis of Visceral Leishmaniasis

Abstract

The study reports an evaluation of the direct agglutination test (DAT) with use of promastigote/amastigote antigen, rk39 strip test, and ELISA for diagnosis of visceral leishmaniasis (VL). Out of 94 clinically suspected VL patients, 16 (17%) were seropositive by all the techniques; in addition, 6 were positive in rk39 strip test and ELISA. On retrospective analysis, out of 16 positive by all the techniques, 11 (69%) had demonstrable Leishmania donovani (LD) bodies in their bone marrow samples, while in 5 bone marrow was not examined. Out of 6 that were positive by ELISA and rk39 strip test, 2 had myelofibrosis and 4 had chronic myeloid leukemia. On the basis of bone marrow aspirate positivity, the sensitivity and specificity of DAT were 100% while those of rk39 strip test and ELISA were 100% and 87%, respectively. The study suggests that DAT appears to be the best technique for the serodiagnosis of VL.