February 20, 2015

expert reaction to new rapid antigen test for Ebola

The World Health Organization has approved the use of a rapid blood test for the detection of Ebola. Though it is less accurate than current tests, it does not require electricity and so can be used more widely.

Prof. David Evans, Professor of Virology, University of Warwick, said:

“One of the early bottlenecks in controlling the outbreak of Ebola in West Africa was the time taken to diagnosis. The gold-standard test uses the polymerase chain reaction (PCR) which necessitates a well-equipped laboratory and trained personnel. It also takes time, both to undertake the test and to transport the patient blood sample to the laboratory for testing. This new test can be used in the field, so significantly reducing time to diagnosis. Since the test detects viral proteins it is likely less sensitive than the PCR assay and so may not detect virus-infected patients until a later stage in infection. This is important because the earlier treatment is initiated the more likely the patient will respond to supportive care. The false-negative rate (i.e. infected patients who are tested and appear uninfected) and false-positive rate (i.e. uninfected patients who are tested and appear to be infected) means the PCR test will remain the gold-standard and must still be conducted. Nevertheless, methods that reduce the time to accurate early diagnosis are clearly desirable.”

Dr Ben Neuman, Lecturer in Virology, University of Reading, said:

“The new antigen test is not a game-changer, but it is another useful tool in the fight against Ebola. 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.”

Declared interests

None declared