An existing blood test for malaria could be adapted to predict if patients treated with artemisinins, the leading class of antimalarial drugs, will later develop severe anemia, a new study said Wednesday.
An estimated 3.2 billion people in 95 countries are at risk of malaria infection, and treatment with a class of drugs called artemisinins is associated with fatality rates lower than five percent.
However, some patients receiving these agents will develop a condition called post-artesunate delayed hemolysis (PADH) weeks after clearance of the malaria parasite, according to the study published in the U.S. journal Science Translational Medicine.
Currently, there are no reliable methods to pinpoint which patients will develop the dangerous complications, which are marked with widespread destruction of red blood cells in those treated with the artemisinin artesunate.
Episodes of PADH have been linked with severe kidney failure, which is one reason why the World Health Organization has called for an urgent need for a simple and reliable test.
In the new study, Papa Alioune Ndour of Paris Descartes University and colleagues repurposed a diagnostic already in use -- the BinaxNOW malaria kit -- to predict PADH with 89-percent sensitivity and 73-percent specificity.
The assay measures remnants of a malaria protein named HRP2 on red blood cells, and was successfully validated using diluted blood samples from 95 Bangladeshi patients and 53 French travelers, all of whom received artesunate.
A separate cohort of 49 patients that were administered quinine, another antimalarial drug, did not have persistently high HRP2 levels.
Quinine is not recommended for use, because it may cause serious side effects, including bleeding and kidney damage.
The researchers noted that the accuracy of the test must be confirmed in larger-scale prospective studies.
"If its accuracy is confirmed, this test may be preferable to routine follow-up of all patients for 28 days," they wrote in the paper. "(It) should ensure a sustained positive outcome in patients with severe malaria treated with artesunate."