Diagnostic Accuracy of Polymerase Chain Reaction Against Giemsa Staining on Tissue Biopsy for Cutaneous Leishmaniasis.

Objective: To evaluate the diagnostic accuracy of a commercial real-time polymerase chain reaction (PCR) kit targeting 18S rRNA against Giemsa-stained tissue slides in patients clinically suspected of cutaneous leishmaniasis (CL).

Study design: Cross-sectional analytical study. Place and Duration of the Study: Department of Microbiology, Armed Forces Institute of Pathology / National University of Medical Sciences, Rawalpindi, Pakistan, from July to December 2022.

Methodology: Samples of skin tissue in 98 patients suspected of CL were evaluated. These samples were subjected to Giemsa-staining for microscopy and real-time PCR. Sensitivity, specificity, and accuracy of the PCR were calculated keeping Giemsa-stained tissue slide microscopy as gold standard.

Results: Out of the 98 tissue samples, 37 were found positive for leishmaniasis on PCR while 13 were found Leishmania positive on microscopy of Giemsa-stained slides. The sensitivity, specificity, and accuracy of the PCR for the detection of Leishmania species were 100%, 71.8%, and 91.8%, respectively with 100% negative predictive value.

Conclusion: This study demonstrates that the commercial PCR is a reliable diagnostic test for the diagnosis of CL. The ease, rapidity, and reliability of the PCR make it a dependable tool in diagnostic repertoire of CL.

Key words: Giemsa stain, Leishmania spp., Polymerase chain reaction, Viasure.