clinical symptoms associated with travel to countries that have identified malarial risk suggest malaria as a diagnosis. malaria tests are not routinely ordered by most physicians so recognition of travel history is essential. unfortunately many diseases can mimic symptoms of malaria (for example yellow fever dengue fever typhoid fever cholera filariasis and even measles and tuberculosis). consequently physicians need to order the correct special tests to diagnose malaria especially in industrialized countries where malaria is seldom seen. without the travel history it is likely that other tests will be ordered initially. in addition the long incubation periods may tend to allow people to forget the initial exposure to infected mosquitoes. the classic and most used diagnostic test for malaria is the blood smear on a microscope slide that is stained (giemsa stain) to show the parasites inside red blood cells. although this test is easily done correct results are dependent on the technical skill of the lab technician who prepares and examines the slides with a microscope. other tests based on immunologic principles exist; including rdts (rapid diagnostic tests) approved for use in the u. s. in 2007 and polymerase chain reaction (pcr) tests. these are not yet widely available and are more expensive than the traditional giemsa blood smear. some investigators suggest such immunologic based tests be confirmed with a giemsa blood smear.
how is malaria diagnosed?