Evaluation of serological diagnostic indices for mucocutaneous leishmaniasis: immunofluorescence tests and enzyme-linked immunoassays for IgG, IgM and IgA antibodies.

The sensitivity, specificity, positive predictive value, negative predictive value, and efficiency of immunofluorescence (IF) and enzyme-linked immunoassays (ELISA) for IgG, IgM and IgA antibodies were assessed on sera from mucocutaneous leishmaniasis patients and controls. The sensitivity of the IgG-ELISA test was 93.3% with 95% confidence interval higher than what could be due to a random test not associated with the disease. The specificity of all tests, except the IgM-ELISA, gave indices that could not have been due to chance. The IgG-ELISA and IgG-IF had the highest positive predictive value and the kappa statistic showed that the strength of agreement between the disease and the test was strongest for IgG-ELISA. The IgG-ELISA had a negative predictive value with 95% confidence limits that were not due to chance alone. Efficiency was highest for IgG-ELISA and IgG-IF. These results were obtained using sera from patients with severe or long-standing disease and from controls in whom the disease was ruled out by a negative Montenegro skin test. In field surveys where the differences between cases and controls are less easy to define the diagnostic indices of these tests may vary with the disease prevalence.