Rapid malaria test kit useful for developing countries

Scientists from Nanyang Technological University, Singapore (NTU Singapore) have developed a test kit for malaria that delivers results in just 30 min. Described in the journal Sensors and Actuators B: Chemical, the kit could facilitate the diagnosis of malaria in the field, as the equipment needed is anticipated to be lightweight, easy to use and able to detect the disease in its early stages.

Microscopic examination of blood infected with malaria parasites remains the current global benchmark to confirm an infection. However, to conduct the process, this requires microscopes and a level of expertise which are often not available in developing countries and rural areas. And while rapid diagnostic tests (RDTs) for malaria do exist, they are unable to detect infections during the early stages of the disease; can give false positive or negative results; and do not determine the severity of the infection.

The NTU test kit could reduce researchers’ reliance on complex laboratory equipment as it would only require a blood sample and water to operate. The kit works by detecting haemozoin, a by-product formed from the digestion of blood by malaria parasites, which is a unique indicator of the disease.

First, 10 microlitres of a patient’s blood, which is less than a drop of water, is mixed with water to force red blood cells to release the parasites contained. A pump within the test kit then sucks in the blood mixture to bring it in contact with several chemical patches, which cause haemozoin to light up. The flashes of light are then picked up by a Raman spectrometer, which determines whether an infection is present or not, as well as its severity.

To validate the accuracy of the test kit, the researchers loaded human blood infected with malaria parasites into the chip. The test could detect early-stage parasites at a level of 125 parasites per microlitre of blood, which is a higher sensitivity than currently available rapid diagnostic tests.

“Compared to current solutions, the NTU-developed test kit is able to detect malaria infections even when the number of parasites in the blood are low, especially during the early stages of the disease,” said NTU’s Associate Professor Liu Quan, who led the study. “It is also able to quantify the number of parasites in every test, which allows physicians to monitor their patient’s progress in fighting the disease.”

The researchers estimate that each test would cost about US$1 per chip to manufacture, which would facilitate low-cost, point-of-care field testing on a large scale. It could therefore be useful for malaria specialists who are conducting research remotely or clinicians without access to laboratory equipment, said NTU’s Professor Laurent Renia, who was not part of the study.

The NTU team has filed a patent application for their technology, on top of an earlier patent they obtained in 2017. The team hopes to find an industry partner to work with and to conduct further trials on their malaria test kit to improve its sensitivity and functionality.

Image caption: Dr Clement Yuen, Research Fellow from NTU’s School of Chemical and Biomedical Engineering, holding a prototype of the rapid malaria test kit. Image credit: NTU Singapore.

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