Canine leishmaniosis: Serological comparison of a commercial rapid test with a quantitative enzyme-linked immunosorbent assay test for detection of anti-Leishmania infantum antibodies

Abstract

Purpose: The aim of this study was to evaluate a serological immunochromatographic test for the detection of anti-Leishmania infantum canine antibodies. Methods & Materials: The rapid test was compared to a reference quantitative serological technique: ELISA in-house (Enzyme-Linked Immunosorbent Assay). This quantitative ELISA in-house was used to define the sera as positive or negative. One hundred canine serum samples were evaluated, 41 were considered negative and 59 were considered seropositive with different levels of anti-Leishmania antibodies: low levels (n=7), medium levels (n=28) and high levels (n= 24). Based on these results, the FASTest® LEISH (Diagsnostik Megacor, Austria) was evaluated: sensitivity, specificity, positive predictive value, negative predictive value, Kappa index and accuracy were calculated. Results: The sensitivity and specificity were 0.97 and 0.98, respectively. In an endemic area to Leishmania infantum infection with a low seroprevalence (10%), the positive predictive value was 0.82 and the negative predictive value was 1.00. By contrast, for a high seroprevalence area (25%), the positive predictive value was 0.93 and the negative predictive value was 0.99. For the Kappa index, FASTest® LEISH obtained 0.95 and the accuracy for this qualitative test was 0.97. Conclusion: The study showed that FASTest® LEISH is a reliable diagnostic test that complies with all requirements for a sensitive (relative sensitivity 97%) and specific (relative specificity 98%) rapid test. Compared to other commercial tests the FASTest® LEISH is a commercial rapid test with high sensitivity and specificity for early detection infected dog with a reasonable cost-benefit balance.