Rapid test kit can correctly identify about 92% of Ebola infected patients and clear 85% of those not infected.
The first rapid test for the Ebola virus, which can deliver a result in 15 minutes, has been approved by the World Health Organisation for use in west Africa.
A quick and easy test that can be used in rural African settings rather than relying on the transportation of samples to distant labs is much needed in the Ebola epidemic, and several companies have been working to produce one. The ReEBOV Antigen rapid test kit, which now has a WHO seal of approval, is made by Corgenix in the US.
Instead of testing for the genetic material of the virus – its nucleic acid – the test detects the Ebola protein. It is less definitive, but trials have shown that it can correctly identify about 92% of Ebola-infected patients and clear 85% of those not infected with the virus.
Delays in confirming that people have the Ebola virus have led to large numbers being held in isolation centres, where those who were virus-free may become infected. The current test takes around four to six hours, but delays in transporting samples to labs and getting results back can mean a diagnosis takes several days.
A rapid test will be of enormous help to health centres and hospitals. It means they can quickly discover which patients arriving with a fever have Ebola and which have something else, commonly malaria. The uncertainty has led to clinics either converting to Ebola holding centres or closing altogether, leaving people with other illnesses with nowhere to go.
Now that the numbers of cases have fallen – there were 128 in the week to 15 February – the rapid test is not as urgently needed as it once was, but it will still help in the drive to get everybody who is infected identified and treated.
“The new antigen test is not a game-changer, but it is another useful tool in the fight against Ebola,” said Dr Ben Neuman, lecturer in virology at the University of Reading. “The new test is small, cheap and portable, but is less sensitive than the gold-standard test that is used to diagnose early-stage Ebola in the clinics now.
“The new test could help to quickly confirm outbreaks in remote areas without the need to send samples to a testing clinic and wait for results. The new test isn’t about saving the lives of infected people, but it can help in the long run by making it easier and quicker to detect Ebola outbreaks.”