A diagnostic performance evaluation of rapid diagnostic tests and microscopy for malaria diagnosis using nested polymerase chain reaction as reference standard in a tertiary hospital in Jos, Nigeria.

Background: Rapid diagnostic tests are frequently used in healthcare settings across Nigeria for diagnosis of Plasmodium falciparum malaria, which is the commonest form of malaria in the country. In this study, the performance of a rapid diagnostic test (RDT) was compared with expert microscopy using the polymerase chain reaction (PCR) as the reference standard in a tertiary hospital in Jos, Nigeria.

Methods: This study was a prospective, cross-sectional, hospital-based study. A total of 200 participants of all ages presenting to Jos University Teaching Hospital with a history of fever or an axillary temperature of >37.5°C were recruited. Blood specimens were collected and malaria testing was done using RDT, microscopy and PCR.

Results: The prevalence of malaria in this study was 17%, 15% and 13% by PCR, microscopy and RDT, respectively. Compared with microscopy, RDT had lower sensitivity of 75% (95% CI: 56.60-88.54) vs 88.24% (95% CI: 72.55-96.70), lower specificity of 98.80% (95% CI: 95.72-99.85) vs 100.0% (95% CI: 97.80-100.0), lower positive predictive value 92.31 (95% CI: 74.89-97.97) vs 100 (95% CI: 98.0-100.0), and lower negative predictive value 95.35 (95% CI: 91.83-97.39) versus 97.65 (95% CI: 94.30-99.05).

Conclusion: The diagnostic performance of expert microscopy was better than RDT in the diagnosis of Plasmodium falciparum malaria. Quality assurance procedures such as using expert microscopy to cross-check a proportion of RDT negative results in patients with clinical features of malaria is desirable.