Development of a New Accurate Lateral Flow Immunoassay for Enhanced Diagnosis of Human Leptospirosis

Abstract

Purpose Leptospirosis is a global neglected disease. Current diagnostic methods are technically complex, expensive, and often inaccurate, primarily confined to specialized laboratories. New simple and accurate tests are mandatory to decentralize and improve diagnosis. Here, we introduced a new lateral flow immunoassay (Lepto-LF) for human leptospirosis. Methods We conducted a double-blinded assay using 104 serum samples from patients with or without leptospirosis, diagnosed according to the standard algorithm. Diagnostic performance of Lepto-LF was estimated across various days from onset of symptoms (dpo), comparing it with the current methods: enzyme-linked immunosorbent assay (IgM-ELISA) and the slide agglutination test using temperature-resistant antigen (SATR). Results Lepto-LF exhibited perfect diagnostic performance with a Youden´s index J = 1, from the acute phase starting at 6 dpo. IgM-ELISA gave slightly lower accuracy (J = 0.91) with 95.5% sensitivity (Se) and specificity (Sp), while SATR showed very poor diagnostic yield (J = 0.41, Se = 95.5%, Sp = 45.5%). Performances remained similar in the convalescence phase of the disease (> 10 dpo). Conclusion Lepto-LF proved to be a reliable test with performance similar to current screening methods but with significant advantages. Due to its simplicity and speed, it can be used in low/medium-complexity labs, providing rapid results for early disease detection and timely treatment during the acute phase when antibiotics are highly effective. Additionally, Lepto-LF can serve as a confirmatory test, especially where the standard MAT is unavailable. Lepto-LF holds promise for remote areas and vulnerable environments, promoting decentralized diagnosis and ensuring equal access nationwide.