Rapid Diagnostic tests for the Laboratory Diagnosis of Malaria

Rapid Diagnostic tests for the Laboratory Diagnosis of Malaria

A rapid diagnostic test (RDT) is an alternate way of quickly establishing the diagnosis of malaria infection by detecting specific malaria antigen (e.g. HRP2- Histidine Rich Protein-2, or Specific PLDHL-Parasite Lactate Dehydrogenase (specific for Falciparum malaria diagnosis).

Technique: A blood specimen collected from the patient is applied to the sample pad on the test card along with certain reagents. After 15 mins, the presence of specific band in the test card window indicate whether the patient is infected with Plasmodium falciparum or one of the other three species of human malaria.

Advantage of Rapid Diagnostic test for Malaria diagnosis)
High quality malaria microscopy is not always available in every clinical settings where patients might seek medical attention. The laboratories associated with these health care settings may now use an RDT to more rapidly determine if their patients are infected with malaria.

Disadvantage of Rapid Diagnostic test (for Malaria diagnosis)
The use of the RDT does not eliminate the need for malaria microscopy. The RDT may not be able to detect some infections with lower number of malaria parasites circulating in the patient's bloodstream. All negative RDT must be followed by microscopy to confirm the result. 

In addition, all positive RDT's should also followed by microscopy. The currently approved RDT detects two different Malaria antigen; one is specific for P. falciparum and the other is found in all four human species of malaria. Thus microscopy is needed to determine the species of malaria that was detected by the RDT. In addition, microscopy is needed to quantify the proportion of RBC's that are infected, which is an important prognostic indicator.