Rapid Test Approach to Malaria Challenged

Rapid Diagnostic Tests (RDT) for malaria, based on antigen detection, might be of help, particularly in peripheral health centers, that most often lack any laboratory facilities.

International experts have suggested that there must be a hard diagnosis of malaria before the disease is treated, as there has been a sharp rise in treatment costs of malaria. Diagnosis and treatment of malaria cannot be delayed, since a mild illness may quickly develop into a life-threatening condition.

Scientists at the Antwerp Institute of Tropical Medicine (Belgium) carried out a study in Burkina Faso to check whether the introduction of malaria rapid tests was worthwhile. The diagnosis is usually made by microscopy: a drop of blood is stained and examined under the microscope. In Africa, especially in poor countries such as Burkina Faso, microscopy is absent in health centers. There a diagnosis is made on the basis of symptoms. A reliable rapid test could provide a solution to this. If the test is positive, the patient is treated for malaria. If it is negative, another cause for the fever must be sought.

The RDT used for the study was the Paracheck test (Orchid Biomedical Systems; Goa, India), the most widely used RDT, based on the detection of the Plasmodium falciparum specific histidine-rich protein II (HRP-2). It diagnoses malaria infection rapidly and with reasonable accuracy according to most studies, with sensitivity for malaria infection ranging from 90.1% to 100%, with specificity from 52% to 99.5%.

The scientists showed that the RDT does not detect all malaria cases, especially in small children who are most vulnerable to the disease. Furthermore, they saw that nurses were still treating four out of five patients for malaria despite a negative test. Because the disease cannot be excluded based on symptoms, the local habit in the case of fever is to treat the patient for malaria. There were also false positive tests from people who carried the malaria parasite, whereby they continued to maintain resistance, but were ill for other reasons. As a result they underwent an unnecessary malaria treatment while, for example, the pneumonia or meningitis that caused fever were not treated. A rapid test costs EUR 0.70, while antimalaria artemisinin therapy costs EUR 1 per child and EUR 2 per adult.

On the RDT approach of the World Health Organization (WHO; Geneva, Switzerland), Zeno Bisoffi, PhD, said, “The test-based approach of WHO is unsuitable for regions where a lot of malaria occurs. The test results are unreliable and it is too expensive to test everyone. On the basis of cost-benefit considerations, a fever-based treatment with a cheap but less effective combination of medicines is an alternative.” The study was presented by Dr. Bisoffi on July 28, 2013, who completed his doctorate with this study.

Related Links:
Antwerp Institute of Tropical Medicine
Orchid Biomedical Systems
World Health Organization