Performance of RPA-LF for Cutaneous Leishmaniasis

Study Overview
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Brief Summary
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CL is public health in the Americas, diagnostic confirmation is required to start treatment, however current diagnostic methods have several limitations and its access is limited. Technical requirements of conventional molecular diagnostics and costs preclude their routine use in primary care facilities in rural areas. A recently developed method of Isothermal Recombinase Polymerase Amplification (RPA) targeting Leishmania kinetoplast DNA, has shown high accuracy in detecting Leishmania Viannia spp. We evaluated the diagnostic performance of the RPA-LF test in a laboratory reference center and field scenario with community participation.

Detailed Description
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CL is public health in the Americas with an average of 55,000 cases per year between 2001 - 2018 in 17 countries, which mainly occur in rural areas with an average of 55,000 cases per year between 2001 - 2018 in 17 countries. Diagnostic confirmation is required to start treatment, however current diagnostic methods have several limitations, and sometimes it is necessary to perform confirmatory tests that are not available in endemic areas. Several molecular diagnostic tests have been developed for the diagnosis of CL, however, the technical requirements and costs of sample processing by conventional or quantitative PCR preclude their routine use in primary care facilities in resource-constrained settings. A recently developed method of Isothermal Recombinase Polymerase Amplification (RPA) targeting Leishmania kinetoplast DNA, coupled with lateral flow (LF) immunochromatographic strip has shown high accuracy in detecting Leishmania Viannia spp. We evaluated the diagnostic performance of RPA-LF test in two scenarios: laboratory reference center and field with community participation.

Official Title
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Diagnostic Performance of a Recombinant Polymerase Amplification Test - Lateral Flow (RPA-LF) for Cutaneous Leishmaniasis in an Endemic Setting of Colombia

Conditions
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Cutaneous Leishmaniasis (Diagnosis)

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Men or women with 2 years of age and over of any ethnic group Ulcerated skin lesions compatible with cutaneous leishmaniasis with two or more weeks of duration Approval of informed consent Exclusion Criteria: Mucosal leishmaniasis Clinical presentations of cutaneous leishmaniasis different of ulcerated lesions

Ages Eligible for Study
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Minimum Age: 2 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Performance of RPA-LF compared with the composite gold standard (smear, culture, histopathology, and q-PCR-18S) in two scenarios: reference laboratory and field. | Sensitivity, specificity, predictive values (positive and negative) and likelihood ratios with their corresponding 95% confidence intervals will be calculated in both scenarios. We define as true positive (TP) when at least one of the gold standard tests (smear, culture, histopathology or q-PCR-18S) and RPA-LF are positive. A patient was considered true negative (TN) when at least smear, q-PCR-18S were negative and, culture and RPA-LF also resulted in negative. Reference lab scenario refers to when the samples are obtained by highly trained technicians (auxiliary nurses) in urban areas localized in Tumaco in a Primary Health facility and send to the reference center in Cali to be processed. In Reference center samples are taken and processed by an expert microbiologist. Field refers when the samples are obtained by trained community health workers (CHW) and processed by a non-expert field technician in Tumaco in a primary health facility. | Feb 2018 - August 2020 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Performace of RPA-LF compared with 4 aditional reference standards in both scenarios. | Sensitivity, specificity , predictive values (positive and negative) and likelihood ratios and 95% confidence intervals will be also estimated using 4 reference tests 1)the same as the gold standard but without qPCR; 2) lesion smear microscopy and culture; 3) lesion smear microscopy read in reference lab and 4) lesion smear microscopy read in the primary health facility in both scenarios. | Feb 2018 - August 2020 |