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.
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
The number of RDTs distributed by national malaria control programmes in the public sector has increased from less than 200 000 in 2005 to more than 74 million in 2011. Manufacturers surveyed by WHO for the World Malaria Report 2012 reported a total of 155 million RDT sales in 2011. Data received from countries reveal that most RDTs (72%) were used in the WHO African Region, followed by the South-East Asia Region (22%). A total of 49 countries reported deployment of RDTs at the community level, and 12 million patients were reported as having been tested through such programmes in 2011. Despite this expansion of diagnostic testing, the majority of suspected malaria cases still do not receive a parasitological test.
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 US Centers for Disease Control and Prevention established a pre-purchase (Product Testing) and post-purchase (Lot Testing) evaluation scheme for RDTs in 2007. This work is being performed in collaboration with several research and public health institutions in endemic countries. As a result of the periodic evaluations of RDT performance completed through this programme, the quality of RDTs has improved dramatically in recent years.
WHO recommendations for RDT procurement eligibility require that RDTs consistently detect at least 75% of low parasite density samples from the "Product Testing" evaluation panel (i.e. at least a 75% "panel detection score"); have a false positive rate of less than 10%, and fewer than 5% invalid tests. WHO provides further guidance to countries on product selection, procurement, implementation (including training) of malaria RDTs for country programmes.
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Last update: 6 March 2013
- Information note on recommended selection criteria for procurement of malaria rapid diagnostic tests (RDTs) (2012)
- Malaria rapid diagnostic test performance. Results of WHO product testing of malaria RDTs: Round 4 (2012)
- Good practices for selecting and procuring rapid diagnostic tests for malaria (2011)
- Universal access to malaria diagnostic testing: an operational manual (2011)
- Guidelines for the treatment of malaria. Second edition (2010)
- Guidance on conducting field trials (2009)
- Transporting, storing and handling malaria rapid diagnostic tests at central and peripheral storage facilities (2009)
- Transporting, storing and handling malaria rapid diagnostic tests in health clinics (2009)