Evaluation of a point-of-care blood test for identification of Ebola virus disease at Ebola holding units, Western Area, Sierra Leone, January to February 2015

Abstract

Current Ebola virus disease (EVD) diagnosis relies on reverse transcription-PCR (RT-PCR) technology, requiring skilled laboratory personnel and technical infrastructure. Lack of laboratory diagnostic capacity has led to diagnostic delays in the current West African EVD outbreak of 2014 and 2015, compromising outbreak control. We evaluated the diagnostic accuracy of the EVD bedside rapid diagnostic antigen test (RDT) developed by the United Kingdom's Defence Science and Technology Laboratory, compared with Ebola virus RT-PCR, in an operational setting for EVD diagnosis of suspected cases admitted to Ebola holding units in the Western Area of Sierra Leone. From 22 January to 16 February 2015, 138 participants were enrolled. EVD prevalence was 11.5%. All EVD cases were identified by a positive RDT with a test line score of 6 or more, giving a sensitivity of 100% (95% confidence interval (CI): 78.2-100). The corresponding specificity was high (96.6%, 95% CI: 91.3-99.1). The positive and negative predictive values for the population prevalence were 79.0% (95% CI: 54.4-93.8) and 100% (95% CI: 96.7-100), respectively. These results, if confirmed in a larger study, suggest that this RDT could be used as a 'rule-out' screening test for EVD to improve rapid case identification and resource allocation.

Tackling emerging infections: clinical and public health lessons from the West African Ebola virus disease outbreak, 2014–2015

“…If science and technology investments in neglected 'tropical' infections are made ahead of time, advances in rapid diagnostics, therapeutics or preventative measures could completely alter an outbreak trajectory, but this requires foresight by scientists, policymakers and research funders. 21,22 …”

Ebola and Health Partnerships, Action in a Time of Crisis

“…He became an integral part of the delivering clinical supervision, assisting in patient management and safety, and providing valuable ongoing training opportunities for junior medical staff [22]. This was particularly important as all school and university level education was suspended in Sierra Leone for a full year.…”

“…The incidence of EVD in Freetown was rapidly decreasing during this time but despite this, the study recruited 138 participants. The test proved highly sensitive and specific and was published in an open access peer-reviewed journal, within two months of study completion [22].…”

Comparative Evaluation of the Diagnostic Performance of the Prototype Cepheid GeneXpert Ebola Assay

“…In recent years, filovirus diagnostics have relied mostly on realtime RT-PCR assays using fluorogenic probes (11)(12)(13)(14)(15)(16)(17)(18)(19). Two prototype point-of-care assays that detect viral antigen by using lateral flow technology were recently evaluated using clinical specimens from suspected EVD cases in Sierra Leon (20,21). In this study, we evaluated the diagnostic performance of the prototype GeneXpert (Cepheid, Sunnyvale, CA, USA) Ebola assay in serum and plasma samples from suspected EVD cases in Sierra Leone.…”