New Rapid TB Test Being Developed in South Africa

A point-of-care rapid diagnostic test for TB has been developed by a multinational team of scientists led by researchers at Stellenbosch University in South Africa.

One of its co-inventors, Professor Gerhard Walzl, spoke to The Conversation Africa’s health and medicine editor Candice Bailey about the advantage of the new test over the current methods.

"If our test is accepted after clinical trials are completed, it will be able to provide almost immediate results. People will be able to be diagnosed and start treatment in a single visit to a health-care facility.

The test is done with blood obtained from a finger prick and can make a TB diagnosis in less than an hour. The diagnostic test is a hand-held, battery-operated instrument that will measure chemicals in the blood of people with possible TB. This test will not have to be done in a laboratory and health-care workers will be able to perform it with minimal training.

It is a low-cost screening test and has the potential to significantly speed up TB diagnosis in resource-limited settings.

With the current tests, samples need to be taken from the stomachs of  young children, as they cannot follow instructions to produce a good quality sputum sample. This requires the use of a nasal tube, which is not pleasant for the child or the health-care worker.

The test also isn’t effective for people living with HIV. This is because their sputum often has low levels of the bacteria, which can lead to a false negative test result.

There is also a molecular test that detects bacterial DNA in the sputum sample. This test only takes two hours to produce a result and although it speeds up the detection of TB, it is not widely available to people in rural areas as instruments are placed in a centralised manner.

The new test's biosignature has been patented and its accuracy and efficacy will be tested in five African countries over the next three years. We will recruit 800 people who have TB symptoms from Namibia, the Gambia, Uganda, Ethiopia and South Africa.

I wish Nigeria was included though.


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