Field Evaluation of rK39 Test and Direct Agglutination Test for Diagnosis of Visceral Leishmaniasis in a Population with High Prevalence of Human Immunodeficiency Virus in Ethiopia

Sep 17, 2026

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Accuracy of an rK39 rapid diagnostic test (DiaMed-IT-Leish®) was evaluated against splenic aspiration and the direct agglutination test (DAT) for diagnosing visceral leishmaniasis (VL) in Ethiopia where HIV prevalence is high. Among 699 clinically suspected patients, 84% were tested for HIV and 34% were HIV positive. Sensitivity was 84% for rK39 and 94% for DAT, while a combined DAT+rK39 algorithm reached 98–99% sensitivity by HIV status. rK39 specificity was 92–99%. rK39 can support decentralized diagnosis, with negative results prompting follow-up DAT testing, especially in HIV-positive cases.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages6

Reading Time15 min

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Abstract

Introduction

Visceral leishmaniasis context and need for accurate testing

Limitations of parasitologic and DAT-based approaches

Diagnostic thresholds and implications for HIV co-infection

Results and diagnostic algorithm implications

View metadata, [citation and similar papers at core](citation and similar papers at core.ac.uk)[.ac.uk](citation and similar papers at core.ac.uk) brought to you by CORE provided by MSF Field Research Am. J. Trop. Med. Hyg., 80(6), 2009, pp. 929–934 Copyright © 2009 by The American Society of Tropical Medicine and Hygiene Field Evaluation of rK39 Test and Direct Agglutination Test for Diagnosis of Visceral Leishmaniasis in a Population with High Prevalence of Human Immunodeficiency Virus in Ethiopia Rachel ter Horst, TewodrosTefera, GessesseAssefa, Abdurazik Z. Ebrahim, Robert N. Davidson, and Koert Ritmeijer* Médecins Sans Frontières, Humera, Ethiopia; Kahsay Abera Hospital, Humera, Ethiopia; Ethiopian Health and Nutrition Research Institute, Addis Ababa, Ethiopia; Department of Infection and Tropical Medicine, Northwick Park Hospital, Harrow, United Kingdom; Médecins Sans Frontières, Amsterdam, The Netherlands Abstract. Accuracy of an rK39 rapid diagnostic test (DiaMed-IT-Leish®) for visceral leishmaniasis (VL) was compared with splenic aspiration and the direct agglutination test (DAT) in a population with a high prevalence of infection with human immunodeficiency virus (HIV) in Ethiopia. There were 699 patients clinically suspected of having VL (153 parasitologically confirmed, 482 DAT confirmed, and 130 DAT negative), and 97 DAT-negative controls. A total of 84% were tested for HIV and 34% were HIV positive. Sensitivity of the rK39 test in parasitologically confirmed VL patients was 84%(77% in HIV positive and 87% in HIV negative; P = 0.25). Sensitivity of the DAT was higher (94%; P = 0.01), 89% in HIV-positive patients and 95% in HIV-negative patients; P = 0.27). Specificity of the rK39 test was 99% in DATnegative controls and 92% in DAT-negative patients clinically suspected of having VL. A diagnostic algorithm combining DAT and the rK39 test had a sensitivity of 98% in HIV-positive VL patients and 99% in HIV-negative VL patients. Despite the lower sensitivity in a population with a high prevalence of HIV, the DiaMed-IT-Leish® rK39 test enables decentralization of diagnosis. Patients clinically suspected of having VL who show negative results on the rK39 antigen test should undergo follow-up DAT testing, especially if they are HIV positive. INTRODUCTION Visceral Leishmaniasis (VL or Kala-azar) is a systemic parasitic disease transmitted by phlebotomine sand flies. The causative parasite in east Africa is Leishmania donovani. Visceral leishmaniasis is endemic in some regions in the southern and northwestern lowlands of Ethiopia. Since 1997, Médecins Sans Frontières (MSF) has established two VL treatment centers in the northwestern leishmaniasis-endemic region of Ethiopia, where 500–2,000 VL patients are treated annually. Because access to treatment is limited, incidence is probably much higher. The prevalence of human immunodeficiency virus (HIV) in the counseling and testing centers in the area is 11–13%(MSF data) and 29% among VL patients.1 Clinical diagnosis of VLis inaccurate.The experience of MSFin eastern Africa is extensive, with more than 80,000 VL cases treated since 1989. In our centers, only approximately 50% of patients fulfilling the clinical case definition for VL (history of fever for > 2 weeks with splenomegaly and/or lymphadenopathy) have confirmed VL; the rest have diseases including malaria, typhoid, or disseminated tuberculosis. Accurate diagnosis is essential. Visceral leishmaniasis is generally fatal if untreated, and sodium stibogluconate, the most commonly used drug for treatment of patients with VL, has serious toxicity. Early diagnosis of VL requires an accurate test that is simple, rapid, does not require a laboratory or refrigeration, non-invasive, and suitable for use in remote settings. Parasitologic diagnosis by direct microscopy of spleen aspirates has a reported sensitivity of 96%,2 but spleen aspirates are impractical and potentially unsafe in remote settings with

FAQs

How was the rK39 test evaluated for diagnosing visceral leishmaniasis?

Its diagnostic accuracy (DiaMed-IT-Leish®) was compared with splenic aspiration and the direct agglutination test (DAT) among patients clinically suspected of VL in Ethiopia.

What did the study find about sensitivity of the rK39 test and DAT in HIV co-infected patients?

Sensitivity of rK39 was 84% in parasitologically confirmed VL, while DAT sensitivity was higher at 94%. The combined DAT and rK39 algorithm achieved 98% sensitivity in HIV-positive VL patients and 99% in HIV-negative VL patients.

What follow-up testing strategy is recommended after a negative rK39 result?

Patients clinically suspected of VL with negative rK39 antigen test results should undergo follow-up DAT testing, particularly if they are HIV positive.

Sep 17, 2026

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