A comparative study of the effectiveness of diagnostic tests for visceral leishmaniasis

We compared the validity of pancytopenia, the formol-gel test (FGT), the indirect fluorescence antibody test (IFAT), the direct agglutination test (DAT), and the rK39 dipstick test as diagnostic criteria for visceral leishma- niasis (VL) in Nepal. Between September 2000 and January 2002, 310 clinical suspects had a bone marrow aspirate, and if negative, a spleen aspirate smear examined for Leishmania donovani. Sensitivity and specificity of all tests were determined compared with parasitology and by latent class analysis (LCA). Compared with parasitology, the sensitivities of the other tests were as follows: pancytopenia 16.3% (95% confidence interval (CI) 11.3�22.5%), FGT 39.9% (95% CI 32.7�47.4%), IFAT 28.4% (95% CI 22.0�35.5%), DAT 95.1% (95% CI 90.8�97.7%), and the rK39 dipstick test 87.4% (95% CI 81.7�91.9%). Sensitivity estimates obtained by LCA were similar, but specificity estimates were substantially higher (DAT 93.7% versus 77.8%; rK39 dipstick test 93.1% versus 77.0%). The DAT or the rK39 dipstick test can replace parasitology as the basis of a decision to treat VL in Nepalese peripheral health services.