Importance of rapid diagnostic testing for Malaria

When malaria-infected mosquito bites, the parasite gets into the bloodstream and cause damage to red blood cells that carry oxygen. With red blood cells count reduced, a person will fall ill within a few days or a week. There are many symptoms of malaria, the main one being a high fever.

If you are having a fever, feeling chills or headache, It is advisable to get the test for malaria infection at the earliest.

There are many types of tests-

• Thick and thin blood smears
• Rapid diagnostic test
• Molecular test
• Antibody test
• Drug resistance test
• Blood test

Parasite-based diagnosis is recommended for the patients suspected of malaria before giving any treatment. Malaria rapiddiagnostic test helps in improving the malaria infection in areas where microscopy services are not available.

A rapid diagnostic test is a type of point care diagnostic that provides the result immediately either at the health facility, screening site or any other health care provider. Blood is taken through a prick on the finger and the test strip is applied. The test strip colour changes and shows the results of whether malaria is there or not. This test does not specify which malaria parasite caused the infection and whether it is minor or major. For more concrete results, the patient needs to go point of care for blood testing.

The point of care test reduces the need for further diagnosis, the treatment is specified and the risk is less. Rapid tests are used in a variety of point of care from homes to clinics and emergency rooms.

The point of care blood test provides the required information for the malaria diagnosis. There is an immune chromatographic test for the detection of malaria antigens is getting popular.

• Antigens

Immune chromatographic tests capture the parasite antigens from the blood with the use of monoclonal or polyclonal antibodies. These tests do not require a lab, electricity or any special equipment.

• Plasmodium aldolase

This is an enzyme of the parasite glycolytic pathway of the blood stages in falciparum. Monoclonal antibodies are specific in the reaction against Plasmodium aldolase.

The rapid diagnostic test is based on different test formats such as dipstick, strip, card, pad, well or cassette. These provide appropriate results concerning safety and manipulation. The benefits offered-

• A clear plan of action is prepared for dealing with the results. This includes drug treatment or the need for further investigation.
• Affordable
• Adequate systems are there that ensures RDT is used correctly and is in good condition.

Accuracy of results

Rapid diagnosis test detects malaria parasites sensitively quite accurately. Sensitivity is determined by the quality of manufacture, species, number, viability, the strain of parasites present, condition of the device, technique used in performing the test and interpretation.

Sensitivity depends on the concentration of target antigen present and varies with parasite density. If the infection is high, then the test will achieve high sensitivity and it is low if the parasite densities are low.

Therefore, sensitivity and specificity should remain high, to distinguish between malaria and non-malarial fevers. High sensitivity is more important as compared to high specificity because a missed parasitaemia may lead to death.

Regardless of the type of disease, RDT is easy to use, requires no special services and minimal training. There is no need for infrastructure or apparatus and can be used at the point of care for blood testing.