Field evaluation of a malaria rapid diagnostic test (ICT Pf)

BACKGROUND: Malaria rapid diagnostic tests (MRDTs) are quick and easy to perform and useful for diagnosing malaria in primary health care settings. In South Africa most malaria infections are due to Plasmodium falciparum, and HRPII-based MRDTs have been used since 2001. Previous studies in Africa showed variability in sensitivity and specificity of HRPIIbased MRDTs; hence, we conducted a field evaluation in Limpopo province to determine the accuracy of the MRDT currently used in public sector clinics and hospitals. METHODS: A cross-sectional observational study was conducted to determine the sensitivity and specificity of an ICT Pf MRDT. We tested 405 patients with fever with ICT Pf MRDT and compared the results with blood film microscopy (the gold standard). RESULTS: The overall sensitivity of the ICT Pf MRDT was 99.48% (95% confidence interval (CI) 96.17 - 100%), while specificity was 96.26% (95% CI 94.7 - 100%). The positive predictive value of the test was 98.48 (99% CI 98.41 - 100%), and the negative predictive value was 99.52% (95% CI 96.47 - 100%). CONCLUSIONS: The ICT Pf MRDT is an appropriate test to use in the field in South Africa where laboratory facilities are not available. It has a high degree of sensitivity and acceptable level of specificity in accordance with the World Health Organization criteria. However, sensitivity of MRDT at low levels of parasitaemia (<100 parasites/µl of blood) in field conditions must still be established.