Diagnostic gaps in light microscopy for malaria case management and control in Dilla Zuria Health Facility, southern Ethiopia

Malaria misdiagnosis has important clinical and public health consequences, including inappropriate treatment, missed infections, ongoing transmission, and weakened malaria control efforts. This study aimed to identify light-microscope misdiagnoses that may affect malaria case management and control efforts. A single-gate design study was conducted among 474 cases attending Dilla Zuria Health Facility. Venous blood samples were examined by light microscopy and subjected to a qPCR assay, which detects Plasmodium falciparum and Plasmodium vivax infections. The level of misdiagnosis, determined using qPCR as the reference standard, is summarized with descriptive statistics. Diagnostic performance metrics, including sensitivity, specificity, predictive values, accuracy, and kappa statistics, were calculated. Using qPCR as the confirmatory reference, the variation between onsite light microscopic diagnoses and qPCR was 24.7% (95/384) for positive cases and 18.8% (17/90) for negative cases. Moreover, the variation documented between onsite light microscopic diagnoses of P. falciparum was 21% (48/228) compared with qPCR, it was 28.3% (32/113) for P. vivax, and 34.8% (15/43) for P. falciparum and P. vivax mixed infection. Notably, 18.8% of microscopy-negative cases were qPCR-positive, possibly due to submicroscopic infections, inadequately prepared blood smears, or incorrectly read blood smears. Malaria diagnosis still relies on microscopy, but low-density and mixed infections are often missed, leading to misdiagnosis and continued transmission. Structured, competency-based, and regular training combined with robust quality assurance is essential to enhance diagnostic accuracy, optimize malaria case management, and support Ethiopia’s ongoing efforts toward malaria control.