The World Health Organization statistics reveal that there have been 11,207 reported deaths and 27,443 cases in the current West African Ebola outbreak. An affordable, rapid diagnostic test would have been an invaluable tool for health workers on the ground, allowing them to quickly identify and isolate infected individuals and curtail the spread of the deadly hemorrhagic virus. Colorado-based Corgenix has manufactured an Ebola detection kit, called ReEBOV, that works with a drop of blood from a finger prick and a test strip that changes color in five to 15 minutes. It is the only rapid diagnostic test for Ebola to have been granted emergency use status by the WHO.
The currently used benchmark test, RealStar RT-PCR, requires analysis of much larger blood samples at a laboratory with a high bio-safety level and trained staff, facilities often not within easy reach of outbreak zones. On the contrary, the new kit requires very little training to use, but one potential drawback is that it needs refrigeration. Manufactured by a German company altona Diagnostics, RealStar also poses risks to those who collect, transport and test the blood samples.
Study's senior author Nira Pollock, of the Boston Children's Hospital, said, "Laboratory results can sometimes take days to return. 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."
For the test trial, Pollock and the research team used both the ReEBOV rapid test and RealStar on 105 suspected Ebola patients in February 2015 at two government-run treatment centers in Sierra Leone, one of three countries hardest hit by the current outbreak. ReEBOV detected all 28 Ebola cases diagnosed by RealStar, a 100% level of sensitivity, but much, much faster.
The researchers concluded that the ReEBOV rapid diagnostic test could be very useful as a rapid test for Ebola virus disease at the point of care in high-risk populations.
The research also revealed some disconcerting data concerning the reliability of the standard test, RealStar. Six of the 77 RealStar-negative cases tested positive with the new ReEBOV kit. And further checks with an alternative RealStar-like test called Trombley, not yet in widespread use, revealed a handful of cases with low levels of the virus that had been missed by both the others. This meant also that the research team could not determine how accurate ReEBOV was in patients in the early phase of infection, when virus levels are low.