DAKAR, 25 April 2009 (IRIN): World Health Organization (WHO) and the non-profit Foundation for Innovative New Diagnostics (FIND) have released the largest, independent laboratory evaluation of malaria rapid diagnostic tests (RDTs) for World Malaria Day, celebrated Saturday.
The evaluation shows that while some tests accurately detect even slight traces of malaria in tropical temperatures, others give false results, missing potentially life-saving diagnoses.
FIND scientist David Bell told IRIN that a countrys temperature, its rate of malaria outbreaks and the type of mosquito spreading the disease determine the appropriate RDT, but that generally, “you want a more sensitive test” able to detect malaria antibodies even at low concentrations.
According to the report, rapid tests CareStart Malaria HRP2 and First Response Malaria Ag HRP2 manufactured by Access Bio and Premier Medical Corporation, respectively, detected in 100 per cent of the tests malaria infections by one type of mosquito.
Both RDTs detected with 95 per cent accuracy infections from two major disease-spreading species even at low concentrations.
The problem until now is that the malaria RDT market has been unregulated, said FIND’s Bell:
– These manufacturers know their tests must meet a bar [of performance in detection], but it is hard and expensive to get [malaria-infected blood] samples to evaluate the tests.
– Collecting blood samples is not easy. We must wait for malaria season. And it is unpredictable how many samples can be taken. Malaria-infested areas are often cut off during the rainy season – when much of malaria hits – due to poor or non-existent roads.
The result has been spotty performance among some of the 60 brands available – and even within tests from the same manufacturer, Bell told IRIN.
Because of this, manufacturers may release RDTs for sale without adequate testing, which can lead to inaccurate diagnoses, according to FIND.
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