Evaluation of a loop-mediated isothermal amplification (LAMP) kit as a molecular diagnostic test for congenital Chagas disease

BESUSCHIO SUSANA; GALLEGO MONTSERRAT; ALEJANDRO G. SCHIJMAN,; ALBERTO PICADO DE PUIG; BENATAR ALEJANDRO; JOSEPH NDUNGU; CRUZ MATA ISRAEL; CARME MUÑOZ; MARIA FLORES

New Orleans

Congreso; ASTMH 67th Annual Meeting; 2018

American Society of Tropical Medicine and Hygiene

A Chagas LAMP kit was recently developed as a ready-to-use diagnostic method with minimal laboratory facilities, but its diagnostic accuracy has not been yet evaluated. This study aimed to challenge the Chagas-LAMP kit in different T. cruzi infection settings.Methods: 171 blood samples were tested by CHAGAS-LAMP and compared to standardized Real Time qPCR. In 125 individuals, 37 infants born to women with Chagas disease for screening congenital Chagas disease, 66 seronegative individuals residing in endemic areas for T.cruzi infection located in Argentina and 22 samples from Chagas disease adults suffering clinical reactivation due to organ transplantation (RCD) Chagas LAMP was an index test conducted following the Standards for Reporting Diagnosis Accuracy Studies. Five RCD cases were monitored after transplantation and treatment with Benznidazole due to clinical diagnosis of reactivation. Results Chagas -LAMP sensitivity and specificity for detecting congenital Chagas disease were 100% and 92.6%, respectively. False positive CHAGAS-LAMP samples were also PCR positive and belonged to umbilical cord samples. Naked eye visualization and detection using the Genie III instrument was 100% concordant. Specificity measured in 66 seronegative individuals from Argentinean endemic regions was 98.5%. In RCD (n=22), sensitivity of CHAGAS-LAMP was 81.81% by naked eye and 68.18% using the Genie III instrument. In the five RCD followed-up patients, 27/29 samples showed concordant CHAGAS-LAMP findings with qPCR . Conclusions: CHAGAS-LAMP kit is a sensitive and specific laboratory tool for rapid and simple detection of T. cruzi infection in congenital Chagas disease and patients with Chagas disease reactivation.