Monday, May 5, 2008

The negatives of false positives: Misdiagnosing malaria leads to fevered complications

“When people are sick in Mali, the doctor will usually tell them they have malaria whether or not they test for it,” Fatou Faye, an infectious diseases researcher and trainer at a privately funded medical laboratory, the Charles Merieux Centre in Bamako recently told IRIN.

“The patients then buy anti-malarial drugs in the street and build up a resistance to treatment.”

Dr. Imelda Bates of the Malaria Knowledge Project says that when doctors misdiagnose malaria, patients may miss real treatments for other serious illnesses like pneumonia and meningitis. Most rural health clinics lack the proper equipment to make a full malaria diagnosis, leaving many patients uncertain what is causing their fevers. Because the potency of malaria strengthens after each fever cycle, many patients simply take anti-malarial drugs as a precaution.

The problem with most blood smears is that most patients already have a considerable amount of the malaria parasite in their bodies, which is picked up by the test, leading to a false-positive test and overdiagnosis.

Health professionals are calling for more funds going towards diagnosis, which would allow those health clinics away from population centers to purchase microscopy equipment that properly count the amount of parasites in blood, a more certain way of diagnosing the illness. This equipment, called rapid diagnosis tests, are inexpensive and can be used by untrained technicians.

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