Evaluation of Urine as a Diagnostic Specimen for Visceral Leishmaniasis in Sudan

Emma Van Rij Bakri Y M

doi:10.4172/2329-891x.1000106

Abstract

Diagnostic methods for visceral leishmaniasis (VL) require invasive specimen sampling. Urine is a potential noninvasive alternative and in the present study the diagnostic performance of direct agglutination test (DAT), based on a freeze dried antigen, and rK39 strip test (InBios, Bio-Rad) on specimens collected in Sudan was assessed. RK39 test had a sensitivity of 72.1% and a specificity of 76.9% on urine and DAT sensitivity was 62.8% and its specificity 69.2%, using initial diagnosis (VL diagnosis was confirmed on clinical and serological basis) as reference in both cases. Tests agreements were fair. Both rK39 as well DAT have potential in diagnosing VL using urine, but results are currently not as good as on the Indian sub-continent.

Highlights

The diagnosis of visceral leishmaniasis (VL) can either be direct via the demonstration by culture of microscopy of Leishmania parasites in lymph node, bone marrow or spleen aspirates or indirectly through serology or molecular biology [1]
Limited information on testing of urine samples with serology is available from East Africa (Sudan and Ethiopia), another VL hot spot, it is well known that both tests have an overall good sensitivity and specificity in that particular region when performed on serum samples; direct agglutination test (DAT): 94.23% and 89.97%, respectively and rK39: 94.48% and 88.75%, respectively [5]
The results of testing urine samples with rK39 strip test or DAT for VL are presented in table 1

Summary

Introduction

The diagnosis of visceral leishmaniasis (VL) can either be direct via the demonstration by culture of microscopy of Leishmania parasites in lymph node, bone marrow or spleen aspirates or indirectly through serology or molecular biology [1]. Direct demonstration is invasive and requires technical expertise and a certain high level of medical precautions, in particular in the case of splenic aspiration (often considered to be the reference standard), as this has the risk of serious bleeding. Molecular biology is not yet field applicable and serological tests, like the direct agglutination test (DAT) or rK39 immunochromatographic rapid tests are often employed as diagnostic methods [1]. There are several reports, in particular from the Indian subcontinent that describes a good diagnostic performance of rK39 strip tests using urine samples [2,3,4]. We initiated a preliminary evaluation of rk strip tests and DAT on urine samples collected in Sudan, which is reported here

Materials and Methods

Results and Discussion

Ethical Approval