Diagnosis of malaria is made with the help of microscopic examination of the blood samples. The symptoms of malaria may resemble flu, gastroenteritis, typhoid or other viral fevers. Thus fever and other symptoms similar to malaria need careful evaluation to diagnose malaria.
Conditions that mimic malaria and need to be ruled out before diagnosis of malaria include:-
History of travel to a high risk zone or a history of bite. Detailed history of travel to endemic areas even brief stopovers should be recorded.
Early diagnosis is important to ensure appropriate, presumptive and accurate treatment and to reduce the risk of life threatening complications and death. A blood sample is usually taken for diagnosis.
Rapid diagnostic tests (RDTs) are also employed for easy detection and take around 2 to 15 minutes. These tests detect parasite antigens. These can be used by relatively untrained staff.
Polymerase chain reaction (PCR) is a more sophisticated method of diagnosing malaria. It is expensive and less available at endemic zones. Parasite nucleic acids are detected using PCR. PCR is most useful for confirming the species of malarial parasite after the diagnosis has been established by either smear microscopy or RDT.
Serology may also be used to detect antibodies against malaria parasites. This can be done using either indirect immunofluorescence (IFA) or enzyme-linked immunosorbent assay (ELISA). Serology does not detect current infection but rather measures past exposure.
Apart from detection of the parasite other tests are also ordered. These include complete blood counts that reveal anemia, low platelet counts and rarely high white blood cell counts.
G6PD activity is seen to prevent side effects of some anti-malarial drugs like primaquine.
Liver and kidney functions are evaluated to rule out organ damage.
Urea and electrolytes are assessed to check for acidosis and low sodium and high creatinine levels.
Blood glucose is assessed as hypoglycaemia is common with falciparum malaria.
Other tests include assessment of blood gases, blood culture, blood clotting studies, chest X ray, urine and stool cultures and examination of the Cerebrospinal fluid (CSF) by lumbar puncture.