New blood test detects Ebola within minutes
Boston: A new on-the-spot blood test can predict the deadly Ebola disease within minutes, according to results from a patient trial which also suggest the method is as accurate as the most widely-used laboratory-based test.
The study is the first to show that a point-of-care Ebola Virus Disease (EVD) test is faster than and as sensitive as a conventional lab-based molecular method used for clinical testing during the recent outbreak in Sierra Leone.
This new rapid diagnostic test (RDT) could cut back on the lengthy process usually required to confirm if a patient has EVD, help identify case contacts, and ultimately curb the spread of Ebola, according to the research published in The Lancet journal.
Currently, diagnosis of EVD requires a full vial of venous blood to be shipped to a laboratory with a high level of biosafety and staff expertise for testing by real-time reverse transcription polymerase chain reaction (RT-PCR).
This method poses substantial risks to the healthcare workers responsible for blood collection, transport, and testing, and efforts to contain the Ebola epidemic in west Africa have been hampered by this slow and complex diagnostic test, researchers said.
“Laboratory results can sometimes take days to return,” said Dr Nira Pollock, senior author and Associate Medical Director of the Infectious Diseases Diagnostic Laboratory at the Boston Children’s Hospital, US.
“Delays like this result not only in the failure to diagnose and treat Ebola-infected patients, but also in individuals without Ebola being admitted to holding units where they may be subsequently infected with the virus,” said Pollock.
“This new test, on the other hand, is capable of detecting the Ebola virus in just a small drop of blood tested at the bedside, and could help us in the fight against Ebola,” Pollock said.
Researchers compared the diagnostic accuracy of the new RDT against the benchmark RT-PCR test being used for clinical diagnosis in the field reference laboratory run by Public Health England at Port Loko in Sierra Leone.
106 suspected Ebola patients admitted to two treatment centres in Sierra Leone during February 2015 were tested by both RDT (performed on a fingerstick blood sample at the point-of-care) and by standard RT-PCR (performed on plasma in the laboratory).
Both RDT (on whole blood) and RT-PCR (on plasma) were also performed on 284 samples in the laboratory.
The RDT detected all confirmed cases of EVD that were positive by RT-PCR in both point-of-care (28/105 patients) and laboratory testing (45/277 patients), with sensitivity of 100 per cent, and a specificity of 92 per cent.