Diagnostic performance of a Recombinant Polymerase Amplification Test-Lateral Flow (RPA-LF) for cutaneous leishmaniasis in an endemic setting of Colombia.

• Main Authors: Alexandra Cossio (Author), Jimena Jojoa (Author), María Del Mar Castro (Author), Ruth Mabel Castillo (Author), Lyda Osorio (Author), Thomas R Shelite (Author), Nancy Gore Saravia (Author), Peter C Melby (Author), Bruno L Travi (Author)
• Format: Book
• Published: Public Library of Science (PLoS), 2021-04-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 1935-2727; 1935-2735; 10.1371/journal.pntd.0009291
• Keywords: Arctic medicine. Tropical medicine; RC955-962; Public aspects of medicine; RA1-1270
• Source: PLoS Neglected Tropical Diseases, Vol 15, Iss 4, p e0009291 (2021)

<h4>Background</h4>Control of cutaneous leishmaniasis by public health systems in the Americas relies on case identification and treatment. Point-of-care diagnostics that can be performed by health workers within or near affected communities could effectively bring the health system to the resource-limited sites providing early diagnosis and treatment, reducing morbidity and the burden of disease.<h4>Methodology/principal findings</h4>A cross-sectional study was undertaken to evaluate the diagnostic test performance of Isothermal Recombinase Polymerase Amplification (RPA) targeting Leishmania kinetoplast DNA, coupled with a lateral flow (LF) immunochromatographic strip, in a field setting and a laboratory reference center. Minimally invasive swab and FTA filter paper samples were obtained by community health workers and highly trained technicians from ulcerated lesions of > 2 weeks' evolution from 118 patients' ≥ 2 years of age in the municipality of Tumaco, Nariño. Extracted DNA was processed by RPA-LF at a reference center or in a primary health facility in the field. Evaluation was based on a composite "gold standard" that included microscopy, culture, biopsy and real-time polymerase chain reaction detection of Leishmania 18S rDNA. Standard of care routine diagnostic tests were explored as comparators. Sensitivity and specificity of RPA-LF in the reference lab scenario were 87% (95%CI 74-94) and 86% (95%CI 74-97), respectively. In the field scenario, the sensitivity was 75% (95%CI 65-84) and specificity 89% (95%CI 78-99). Positive likelihood ratios in both scenarios were higher than 6 while negative likelihood ratios ranged to 0.2-0.3 supporting the usefulness of RPA-LF to rule-in and potentially to rule-out infection.<h4>Conclusions/significance</h4>The low complexity requirements of RPA-LF combined with non-invasive sampling support the feasibility of its utilization by community health workers with the goal of strengthening the diagnostic capacity for cutaneous leishmaniasis in Colombia.<h4>Trial registration</h4>ClinicalTrials.gov NCT04500873.