The World Health Organisation has approved a rapid test for Ebola, in a potential breakthrough for ending an epidemic that has killed almost 10,000 people in West Africa.
The 15-minute test is a little less accurate than the so-called gold standard of lab assessment, but does not need electricity or highly trained personnel to use it, WHO spokesman Tarik Jasarevic said.
“It’s a first rapid test. It’s definitely a breakthrough,” he said.
The standard laboratory test has a turnaround time of 12-24 hours. While the rapid test is not failsafe, it could quickly identify patients who need quarantine and make it much easier to verify rapidly any new outbreaks.
“Where possible, obviously results from this antigen rapid test should be confirmed by testing by blood sample using normal PCR (polymerase chain reaction) tests,” Mr Jasarevic added, referring to a DNA analysis to detect the disease.
The so-called ReEBOV Antigen Rapid Test, manufactured by Corgenix, involves putting a drop of blood on a small paper strip and waiting 15 minutes for a reaction in a test tube.
It is able to correctly identify about 92 per cent of Ebola infected patients and 85 per cent of those not infected with the virus, the WHO said.
Knowing that margin of error is a major help, said Robyn Meurant, from the WHO’s department of essential medicines and health products.
“The big fear has been that the market gets flooded with tests of unknown quality, or unknown performance, and with Ebola you need to know what are the limitations,” she said.
“A false negative has enormous implications. So does a false positive.
“So this is not a perfect test but… for a rapid test, (it is) not too bad at all.”
She said it would be especially useful if a cluster of suspected cases flared up.
“If you had five patients with suspected symptoms and you went ahead and tested them and they were all positive you’d have a high degree of confidence that you’ve got Ebola,” she said.
Mr Jasarevic gave no details as to where and when the test would be introduced, but did indicate it would likely be bought by a United Nations agency.
The health charity Medecins Sans Frontieres, which has been at the forefront of the fight against Ebola, had also expressed an interest, he said.
Health watchdogs are keen on a fast test because the current PCR test, which looks for telltale genetic signatures, can take up to 24 hours.
A simple but reliable test would help doctors in the field to quarantine people likely to have the virus and airports to test passengers before they get on a flight.
“The new antigen test is not a game-changer, but it is another useful tool in the fight against Ebola,” said Ben Neuman, a virologist at Britain’s University of Reading.
“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.”
Other prototype fast-track tests have been devised by scientists in Britain and France.
As of February 15, WHO said 23,253 people had been infected with Ebola and 9,380 had died, the vast majority of them in Guinea, Sierra Leone and Liberia.
AFP/Reuters