Malaria

When to request this test

• The diagnosis of malaria must be consideredin the presence of any fever in a patient living in an endemic zone.
• Physicians don’t have to wait for a fever episode to perform the diagnostic test. As soon as the diagnosis is suspected, the test and its results are emergencies.
• In the absence of specific clinical manifestations: the diagnosis of malaria must be evoked in the presence of any fever or history of fever, isolated or associated with general, digestive or respiratory symptoms, in a patient during or after a stay in an endemic zone, even if prophylaxis has been taken.
• The clinical presentation can be polymorphous: fever may be isolated, and often cyclic. The main clinical symptoms are those of an hemolytic fever: fever, chills, splenomegaly and jaundice. Other symptoms like headaches, muscle pain, nausea, vomiting, diarrhea and neurological disorders may also be present.
• Any episode of malaria can progress to a severe form, leading to patient death: delayed diagnosis and/or inappropriate treatment are always implicated in the occurrence of these severe episodes.

Biological signs include:

• A near constant thrombocytopenia
• Normal leukocytes count or leukopenia despite high fever, anemia
• High inflammatory syndrome and disturbed liverfunction tests
• Signs of hemolysis (LDH, haptoglobin) are inconstant

Interferences & limitations

• Low parasitic load, coinfection with multiple Plasmodium species can complicate identification, as different species may present differently on microscopic examination
• Cross reactivity: certain rapid tests or antigen tests may cross-react with other species or organisms, leading to false positives (for example, some RDTs may cross-react with Plasmodium falciparum antigens, even in low-parasite cases)
• Persistent antibodies or antigens from a previous Plasmodium infection may cause false positives in some serological tests, even if the person is no longer infected
• Antimalarial drugs used prior to testing