Comparison of a qualitative immunochromatographic test with two quantitative serological assays for the detection of antibodies to Leishmania infantum in dogs

Canine leishmaniosis is a disease caused by Leishmania infantum, a vector-borne parasite. Due to the zoonotic potential of canine leishmaniosis, infected dogs must be identified. Serological assays are the most common methods for the detection of L. infantum infection in dogs used in veterinary practice. The aim of the study was to assess the performance of a rapid immunochromatographic test (FASTest LEISH (R), MEGACOR Diagnostik) for the detection of specific antibodies to that of the L. infantum in dog sera. The results were simultaneously compared using a commercial brand of indirect immunofluorescence antibody test and an in-house enzyme-linked immunosorbent assay as references. Between the two reference tests, 232 serum samples out of 244, produced concordant results while 12 exhibited discordant results. Of the 232 concordant samples, 121 were classified as L. infantum seropositive, and 111 samples were previously classified as L. infantum seronegative by a combination of the reference assays. All samples that were seropositive by the reference tests were also positive according to the rapid test, and only one sample that was seronegative according to the two reference assays was positive according to the rapid test. Compared with the reference tests, the rapid test sensitivity was 100%, specificity was 99.1%, accuracy was 99.6%, Cohen's kappa coefficient was 0.99, and the area under receiver operating characteristic curve was 0.995. The FASTest LEISH (R) is a rapid, qualitative in-clinic test with high sensitivity and specificity.