Rapid diagnostic tests
WHO recommends prompt parasite-based diagnosis in all patients suspected of malaria before treatment is administered. Malaria rapid diagnostic tests (RDTs) have the potential to greatly improve the quality of management of malaria infections, especially in remote areas with limited access to good quality microscopy services.
RDTs are relatively simple to perform and interpret, they rapidly provide results, require limited training, and allow for the diagnosis of malaria at the community level.
Various types of RDTs on the market
Malaria RDTs detect specific antigens (proteins) produced by malaria parasites that are present in the blood of infected individuals. Some RDTs detect a single species (either P. falciparum or P. vivax), some detect multiple species (P. falciparum, P. vivax, P. malariae and P. ovale) and some further distinguish between P. falciparum and non-P. falciparum infection, or between specific species. Blood for the test is commonly obtained from a finger-prick and results are available within 15–30 minutes. Though there are variations among the more than 200 malaria RDT products on the market, the principles of the tests are similar.
Expansion in RDT use
In recent years, RDT testing has been significantly expanded around the world. Manufacturers surveyed by WHO for the World malaria report 2017 reported a total of 312 million RDT sales in 2016. In the WHO African Region, where the disease burden is highest, manufacturer deliveries of RDTs increased from 240 million in 2015 to 269 million in 2016.
Quality assurance and performance testing of RDTs
To assist ministries of health in endemic countries, UN agencies and major procurers, WHO, the Foundation for Innovative New Diagnostics (FIND) and the Centers for Disease Control and Prevention established a pre-purchase (Product Testing) and post-purchase (Lot Testing) evaluation scheme for RDTs in 2007. As a result of the periodic evaluations completed through this programme, the quality of RDTs has improved dramatically in recent years.
Since the beginning of 2018, the coordination of product evaluations is managed by the WHO Programme for the Prequalification of in vitro diagnostics (IVDs).
- Read more on the WHO-FIND malaria RDT evaluation programme
- Read more on the WHO Programme for the Prequalification of IVDs
Further guidance on product selection and procurement
For procurement, WHO recommends that P. falciparum RDTs be prequalified and that all other RDTs meet the following minimum performance requirement:
- at least a 75% "panel detection score" for low parasite density samples from the product testing evaluation panel;
- a false positive rate of less than 10%; and
- fewer than 5% invalid tests.
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- Good practices for selecting and procuring rapid diagnostic tests for malaria
- Guidelines for the treatment of malaria. Third edition
- Malaria rapid diagnostic test performance. Results of WHO product testing of malaria RDTs: round 7 (2015-2016)
- Protocol for estimating the prevalence of pfhrp2/pfhrp3 gene deletions among symptomatic falciparum patients with false-negative RDT results
- Recommended selection criteria for procurement of malaria rapid diagnostic tests
- Transporting, storing and handling malaria rapid diagnostic tests at central and peripheral storage facilities
- Transporting, storing and handling malaria rapid diagnostic tests in health clinics
- Universal access to malaria diagnostic testing – An operational manual