The need for quality assurance of malaria RDTs

Malaria rapid diagnostic tests (RDTs) are affected by various conditions of manufacture, storage and use that can impair the tests’ accuracy and reliability. A comprehensive quality assurance system ensures that test quality is maintained, reducing the likelihood of misdiagnosis and maintaining the confidence of health service providers and consumers in the test’s performance.

What is a quality assurance process for malaria RDTs?

Quality assurance is defined as a total process both inside and outside the laboratory. This process includes the development and implementation of performance standards, Good Laboratory Practice and management skills to achieve and maintain a quality service and provide for continuous improvement. The purpose of quality assurance of malaria RDTs is to provide reliable, relevant and timely test results that are interpreted correctly, thereby increasing efficiency and effectiveness, enhancing patient satisfaction and decreasing costs brought about by misdiagnosis.

Quality assurance also includes monitoring of the RDTs’ diagnostic performance; training and monitoring of preparation and interpretation by end-users; and processes to minimize environmental insult.

Quality control (QC) describes all the activities undertaken by a laboratory to monitor each stage of the test procedure to ensure that tests are performed correctly and are accurate and precise.

WHO quality assurance scheme for malaria RDTs

In 2008, WHO and the Foundation for Innovative New Diagnostics (FIND) established an international quality assurance scheme, executed in collaboration with the United States Centers for Disease Control and Prevention. The aim was to support regulatory approval of malaria RDTs in many endemic countries, considering the heterogeneous diagnostic performance of malaria RDTs in the market. This scheme requires manufacturers to provide evidence of a good quality management system (ISO 13485:2003) and offers comparative performance, thermal stability and ease of use data on RDTs (WHO product testing) to inform procurement.

The same reference materials are used to conduct pre-deployment quality testing (lot testing) at the WHO-recognized lot testing facilities (Research Institution for Tropical Diseases in the Philippines). Since 2019, WHO prequalification of malaria RDTs has become a requirement for procurement of all HRP2, pan-LDH and/or pv-LDH combination RDTs by WHO and several international agencies. Laboratory diagnostic performance, together with dossier review and inspection of the manufacturing facility are the 3 main components of WHO prequalification.

WHO and partners have developed generic job aids and a training manual for health workers, based on trials in Asia and Africa with several partners. These materials are available in English and French, and can be adapted to other languages.

Instructions for RDT preparation and interpretation should be clear and concise in the local languages. Health workers using the tests should be trained and assessed, and systematically monitored on test preparation and interpretation. As RDTs must be read soon after preparation, this should be done on real cases, rather than by review of previously prepared tests. The entire quality chain must be underpinned by appropriate handling/transport and storage practices. Responsibility for overseeing quality assurance processes should be clearly defined and coordinated at a central level. Quality assurance should be an integral part of RDT budgets and implementation plans, as it forms an important part of any microscopy-based programme.