Point-of-care Ebola test developed in the UK

The UK’s Defence and Science Technology Laboratory (DSTL) has developed a new diagnostic test for the Ebola virus which is said to offer significant advantages over the current testing method. A multinational team of scientists from Sierra Leone, South Africa, and the UK reported on the performance of the new device in the journal Eurosurveillance.

“Current Ebola virus disease (EVD) diagnosis relies on reverse transcription-PCR (RT-PCR) technology, requiring skilled laboratory personnel and technical infrastructure,” the authors stated. “Lack of laboratory diagnostic capacity has led to diagnostic delays in the current West African EVD outbreak of 2014 and 2015, compromising outbreak control.”

Dr Andrew S Thompson, a senior analyst from research and consulting firm GlobalData, said the DSTL’s new point-of-care device is a bedside rapid diagnostic antigen test (RDT) which utilises the patient’s capillary blood, rather than venous blood. This means a thumb prick sample is sufficient and there is less risk to healthcare workers of cross-infection through exposure to contaminated blood. He added that the test can be performed in the ward (minimising the risks of exposure through transport to a laboratory), needs no specialist equipment and requires very little training.

The scientists compared the diagnostic accuracy of the RDT with the Ebola virus RT-PCR in 138 patients in an operational setting in Sierra Leone. Dr Thompson said the test was “shown to be very successful in diagnosing patients admitted to hospital, and who were therefore symptomatic for Ebola, [but] no such testing was carried out on asymptomatic patients in a non-hospital setting”.

Dr Thompson noted that lateral flow assays such as the new RDT are less sensitive than PCR assays, and while the team testing the RDT hypothesised that it may show greater sensitivity than existing gold-standard PCR tests, “this has yet to be demonstrated”. He added that because viruses such as Ebola generally only result in transient outbreaks in poverty-stricken regions, there is little justification to establish permanent, high-grade, molecular diagnostic testing if it comes at the cost of more pressing and basic healthcare needs.

Dr Thompson concluded that new tests like the RDT “remain the best way for point-of-care testing for rare and emerging infectious diseases”. However, he suggested that these are “likely to be overtaken by miniaturised nucleic acid-detection platforms, which can truly bring the gold standard of testing out of the laboratory and onto the hospital ward”.