Evaluation of the NovaLisa™ <i>Leishmania Infantum</i> IgG ELISA in A Reference Diagnostic Laboratory in A Non-Endemic Country

• Main Authors: Christen Rune Stensvold, Amalie Vang Høst, Salem Belkessa, Henrik Vedel Nielsen
• Format: Article
• Language: English
• Published: MDPI AG 2019-02-01
• Series: Antibodies
• Subjects: parasite; clinical microbiology; vector-borne disease; leishmaniasis; diagnosis; diagnostic methods; molecular epidemiology
• Online Access: https://www.mdpi.com/2073-4468/8/1/20

Anti-<i>Leishmania</i> antibodies may be detectable in patients with leishmaniasis. Here, we compared a commercial enzyme-linked immunosorbent assay (ELISA) for the detection of anti-<i>Leishmania</i> antibodies, with an immunofluorescence antibody test (IFAT) that is no longer commercially available. Eighty-six serum samples from 73 patients were tested. The results obtained by the NovaLisa&#8482; <i>Leishmania infantum</i> IgG ELISA, interpreted according to the instructions of the manufacturer, but with a modified cut-off for borderline positive values, were compared with the IFAT results that were already available. Moreover, <i>Leishmania</i> Western blot IgG results were available for 43 of the samples. The overall concordance of ELISA and IFAT was 67%. The ELISA and IFAT tests scored as 24% and 15% of the samples being positive, respectively, while 13% and 33% scored as borderline-positive, respectively. Using a Western blot (WB) as the reference, the sensitivities and specificities for the positive plus borderline-positive samples combined was 95.5% (95% confidence interval (CI), 77.2&#8315;99.9%) and 81.0% (95% CI, 58.1&#8315;94.6%) for ELISA, and 95.5% (95% CI, 77.2&#8315;99.9%) and 42.9% (95% CI, 21.8&#8315;66.0%) for IFAT, respectively. Overall, the ELISA proved to be a cost-effective alternative to the IFAT, due to its higher accuracy and specificity, and with a consequently lower number of confirmatory WB tests being required. Lastly, we also present data on the associations between seroconversion and the type of leishmaniasis.