Diagnostic performance of Sysmex XN-31 automated hematology analyzer compared to microscopy and PCR for detecting and quantifying malaria parasites in clinical settings of Oromia Regional State, Ethiopia

Abstract Background Malaria remains a significant public health challenge in Ethiopia. To achieve malaria free country with improved clinical care and support, innovative diagnostic tools are needed. The Sysmex XN-31 automated malaria analyzer, which detects malaria-infected red blood cells was assessed in clinical settings in Ethiopia. This study compared the performance of Sysmex XN-31 automated analyzer with microscopy and polymerase chain reaction (PCR) tests. Methods We conducted a facility-based cross-sectional study in two public hospitals from April to September 2024. Febrile patients suspected of malaria who visited the outpatient departments at Shashamene Comprehensive Specialized Hospital and Meki Primary Hospital were enrolled with consent. Finger prick and four milliliters of venous blood were collected in EDTA tubes from each study participant. The diagnostic performance of the Sysmex XN-31 hematology analyzer for malaria parasite detection and quantification was compared to expert microscopist and qPCR. We also evaluated the usability of the Sysmex XN-31 analyzer in near-patient settings at both sites. Statistical analysis was performed using SPSS 27 and Medical Statistical Calculator v23. Sensitivity, specificity, predictive values, and kappa statistics were calculated. Results Of the 400 suspected febrile cases, malaria positivity was 22.2% (n = 89), 21% (n = 84), 19.2% (n = 77), 18.8% (n = 75), and 16.2% (n = 65) by PCR, Sysmex XN-31, expert microscopist, field microscopist, and RDT, respectively. The sensitivity and specificity of Sysmex XN-31 were 93.5% and 96.6%, respectively, compared with the expert microscopist. However, with PCR as the reference, Sysmex XN-31’s sensitivity dropped to 84.3%, with a slight increase in specificity to 97%. The Sysmex-XN-31 exhibited high negative predictive value (NPV) reliability when compared with field and rapid diagnostic test (RDT) results, based on hypothetical community malaria prevalence. We found strong agreement (89.9%) between Sysmex XN-31 and the field microscopist, with a kappa value of 0.68. The usability test of the Sysmex XN-31 by most participants indicated that errors could be resolved easily, interruptions were manageable, and the interpretation of results was straightforward. Conclusions The Sysmex XN-31 automated hematology analyzer offers high sensitivity and specificity compared to expert microscopist and PCR methods, significantly enhancing malaria surveillance and elimination efforts. It can detect and count malaria parasites while also providing a CBC. With a rapid turnaround time of 55 samples in one hour, it is much faster than traditional testing methods.