Quality assurance of malaria rapid diagnostic tests used for diagnostic confirmation of malaria in rural Tanzania: microscopy versus real-time polymerase chain reaction

In response to the limited availability of quality microscopy services, the use of antigen-detecting malaria rapid diagnostic tests (RDTs) has increased in many malaria-endemic countries. This study aimed to monitor the quality of RDT performance in selected health facilities in rural Tanzania using two quality assurance (QA) methods: reference microscopy and detection of parasite DNA by real-time quantitative polymerase chain reaction (qPCR) on dried blood spots (DBS). The study was conducted in 12 health facilities in Iringa Region, Tanzania, which had high utilization rates and were selected to participate in the study. The facilities included hospitals, health centers, and dispensaries, and were targeted to receive RDTs as part of the national roll-out program. The RDTs used in the evaluation were those available at government facilities through the Ministry of Health and Social Welfare, including SD Bioline, ParaHIT, and Paracheck. Blood samples for QA were collected from patients undergoing RDT for diagnostic confirmation of malaria during two to three consecutive days per month. Stained blood smears (BS) were first examined at the district hospitals (BS1) and then at a reference laboratory (BS2). Discordant BS1 and BS2 results prompted a third examination. Molecular analysis was carried out at the Ifakara Health Institute laboratory in Bagamoyo. The results showed that malaria RDTs had a higher positivity rate (6.5%) than qPCR (4.2%) or microscopy (2.9% for BS1 and 2.5% for BS2). Poor correlation was observed between RDT and BS results, challenging the utility of these tests for RDT QA. Many challenges related to qPCR processing were recorded, and long delays in obtaining QA test results for both microscopy and qPCR were noted. The study concluded that there was limited agreement among the three diagnostic approaches, and neither microscopy nor qPCR appear to be good QA options for RDTs under field conditions. The findings highlight the need for a practical quality assurance procedure for RDTs that can be adopted nationwide. The study's results have implications for the implementation of RDTs in resource-poor settings, where the accuracy of diagnostic tests is critical for effective malaria control. The Tanzanian Ministry of Health and Social Welfare, through the National Malaria Control Programme (NMCP), began to deploy RDTs in 2010 in selected regions as a way to expand and strengthen malaria diagnostic capacity throughout the country. The NMCP recognized the need for a suitable QA method that could be adopted nationwide. The Ifakara Health Institute, in collaboration with the US Centers for Disease Control and Prevention (CDC) Malaria Branch and the U.S. President's Malaria Initiative (PMI), undertook a study to assess two methods of RDT QA and their timeliness. The study's findings have significant implications for the implementation of RDTs in resource-poor settings, where the accuracy of diagnostic tests is critical for effective malaria control. The results highlight the need for a practical quality assurance procedure for RDTs that can be adopted nationwide. The study's conclusions emphasize the importance of developing and implementing effective QA methods for RDTs to ensure accurate diagnosis and effective treatment of malaria.