Stothard J.R., Nabatte B., Sousa-Figueiredo J.C., Kabatereine N.B.
Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom; Vector Control Division, Ministry of Health, P.O. Box 1661, Kampala, Uganda; Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, United Kingdom
Stothard, J.R., Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom; Nabatte, B., Vector Control Division, Ministry of Health, P.O. Box 1661, Kampala, Uganda; Sousa-Figueiredo, J.C., Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, United Kingdom; Kabatereine, N.B., Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
Malaria microscopy in sub-Saharan Africa is often restricted by access to light microscopes. To address this gap, a novel portable inverted monocular microscope, the Newton Nm1, was designed and is now commercially available. Its diagnostic performance was assessed in a blinded-slide trial at ×1000 (oil) of Giemsa-stained thick blood films against a conventional microscope as undertaken by four Ugandan Ministry of Health technicians. With the Newton Nm1, diagnostic performance was: sensitivity 93·5% (95% confidence interval (CI) 78·6-99·2%), specificity 100·0% (95% CI 82·4-100·0%), positive predictive value 100·0% (95% CI 88·1-100·0%) and negative predictive value 90·5% (95% CI 69·6-98·8%). Discordance was due to a systematic error underestimating parasitaemia by ∼45%; when counting Plasmodium parasites against 200 white blood cells, blood films with low parasitaemia (i.e. <100 μL-1 of blood) could be overlooked and misclassified. By contrast, specificity was excellent with no false positives encountered. Whilst proven useful, especially in resource-poor environments, it is still unclear how we can ensure the uptake of the Newton Nm1 within sub-Saharan Africa. Copyright © 2014 Cambridge University Press.
adult; Article; child; diagnostic test accuracy study; female; film; Giemsa stain; human; infant; laboratory diagnosis; leukocyte; malaria; malaria microscopy; microscope; microscopy; nonhuman; parasitemia; Plasmodium; point of contact; portable inverted monocular microscope; predictive value; priority journal; schistosomiasis; sensitivity and specificity; systematic error; Uganda; Plasmodium parasites