Dados do Trabalho

Título

Retrospective evaluation of the performance of diagnostic assays for visceral leishmaniasis

Introdução

Clinical suspicion of visceral leishmaniasis (VL) needs to be complemented by diagnostic assays. However, there is no standardization of a diagnostic flow with available assays.

Objetivo(s)

This study aimed to evaluate the performance of parasitological, molecular, and serological assays used in the diagnosis of VL and propose a diagnostic flow based on performance, practicality, and invasiveness.

Material e Métodos

We carried out a descriptive and cross-sectional study of a 10-year retrospective (2010-2020) routine diagnosis of the Brazilian National Reference Laboratory for VL diagnosis. The tests were statistically evaluated for their performance, positivity in relation to the results of other tests and percentage of change in results in repeated exams.

Resultados e Conclusão

It was evaluated 29.999 assays, including all serological, molecular, and direct tests and 932 individuals met the criteria for this study. By the flow proposed here, individuals with suspected VL must be initially screened by an immunochromatographic test (ICT) with rK39 antigen on the nitrocellulose membrane, followed by a blood polymerase chain reaction (PCR) for Leishmania sp. kDNA, and direct parasitological exam and/or PCR in bone marrow aspirate. A positive result in any of these assays has the potential to define a case of VL. The diagnostic flow should be repeated for negative patients in whom clinical suspicion persists. Repeat ICT within five days obtained a positivity similar to bone marrow examination in patients with non-reactive ICT. The proposed flow has the potential to standardize and improve the diagnosis of VL, reducing the need for more invasive tests without compromising the accuracy of the diagnosis.

Palavras-chave

Visceral leishmaniasis. Diagnostic flow. Polymerase chain reaction. Direct parasitological examination. Immunochromatographic tests.