ReEBOV Antigen Rapid Test kit for Point-of-Care and
Laboratory-Based Testing for Ebola Virus Disease: A Field
By Mara Jana Broadhurst, John Daniel Kelly, Ann Miller, Amanda Semper, Daniel Bailey, Elisabetta Groppelli, Andrew Simpson, Tim Brooks, Susan Hula, Wilfred Nyoni, Alhaji B Sankoh, Santigi Kanu, Alhaji Jalloh, Quy Ton, Nicholas Sarchet, Peter George, Mark D Perkins, Betsy Wonderly, Megan Murray, Nira R Pollock
June 26, 2015
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At present, diagnosis of Ebola virus disease requires transport of venepuncture blood to field
biocontainment laboratories for testing by real-time RT-PCR, resulting in delays that complicate patient care and
infection control efforts. Therefore, an urgent need exists for a point-of-care rapid diagnostic test for this disease. In
this Article, we report the results of a field validation of the Corgenix ReEBOV Antigen Rapid Test kit.
Methods We performed the rapid diagnostic test on fingerstick blood samples from 106 individuals with suspected
Ebola virus disease presenting at two clinical centres in Sierra Leone. Adults and children who were able to provide
verbal consent or assent were included; we excluded patients with haemodynamic instability and those who were
unable to cooperate with fingerstick or venous blood draw. Two independent readers scored each rapid diagnostic test,
with any disagreements resolved by a third. We compared point-of-care rapid diagnostic test results with clinical realtime
RT-PCR results (RealStar Filovirus Screen RT-PCR kit 1·0; altona Diagnostics GmbH, Hamburg, Germany) for
venepuncture plasma samples tested in a Public Health England field reference laboratory (Port Loko, Sierra Leone).
Separately, we performed the rapid diagnostic test (on whole blood) and real-time RT-PCR (on plasma) on
284 specimens in the reference laboratory, which were submitted to the laboratory for testing from many clinical sites
in Sierra Leone, including our two clinical centres.
In point-of-care testing, all 28 patients who tested positive for Ebola virus disease by RT-PCR were also positive
by fingerstick rapid diagnostic test (sensitivity 100% [95% CI 87·7–100]), and 71 of 77 patients who tested negative by
RT-PCR were also negative by the rapid diagnostic test (specificity 92·2% [95% CI 83·8–97·1]). In laboratory testing, all
45 specimens that tested positive by RT-PCR were also positive by the rapid diagnostic test (sensitivity 100% [95% CI
92·1–100]), and 214 of 232 specimens that tested negative by RT-PCR were also negative by the rapid diagnostic test
(specificity 92·2% [88·0–95·3]). The two independent readers agreed about 95·2% of point-of-care and 98·6% of
reference laboratory rapid diagnostic test results. Cycle threshold values ranged from 15·9 to 26·3 (mean 22·6 [SD 2·6])
for the PCR-positive point-of-care cohort and from 17·5 to 26·3 (mean 21·5 [2·7]) for the reference laboratory cohort.
Six of 16 banked plasma samples from rapid diagnostic test-positive and altona-negative patients were positive by an
alternative real-time RT-PCR assay (the Trombley assay); three (17%) of 18 samples from individuals who were negative
by both the rapid diagnostic test and altona test were also positive by Trombley.
The ReEBOV rapid diagnostic test had 100% sensitivity and 92% specificity in both point-of-care and
reference laboratory testing in this population (maximum cycle threshold 26·3). With two independent readers, the
test detected all patients who were positive for Ebola virus by altona real-time RT-PCR; however, this benchmark itself
had imperfect sensitivity.
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