New Ebola test could falsely classify healthy people as Ebola positive


A new rapid diagnostic kit which could be deployed in Congo to detect Ebola could generate false positives, fuelling a fake Ebola outbreak.

The researcher Ameh James states in a study published in Virology that a positive marker for Ebola also appeared when a control assay had no Ebola.

“We note that a faint band was sometimes observed in no template negative controls, however, this faint band was clearly distinguishable from true positives, as demonstrated by ImageJ analysis of black pixel density. Such image analysis could be performed in field situations through the use of a lateral flow reader. “

An accompanying figure actually shows a considerable overlap in the markers between true and false positives, and risking a situation in which people in the Congo without Ebola could be falsely classified as infected with Ebola and forced into treatment if the test is used.

http://www.xinhuanet.com/english/2018-05/16/c_137182397.htm

A new rapid-test kit for Ebola could help contain an outbreak of the deadly virus in the Democratic Republic of Congo, according to latest Australian research.

“This test aims to take about 30 minutes and you can do a simple blood test, get results on the spot and doctors will know whether people should be either treated, monitored or quarantined,” Australia’s University of the Sunshine Coast researcher Ameh James, who is developing the test, said in a statement on Wednesday. 

“The turnaround time for testing is critical in terms of patient treatment, but what is happening is that patients are sent home for up to three days waiting for their results. In that time, they can easily infect their families and others.” 

James, whose work on the new test has been published in the Virology Journal, said the priority now is to secure funding and support for the research, to send kits to affected areas and train people to use them to gain vital data on the efficacy of the test, while potentially preventing people from infecting others.

“We would also be able to collect the data we need to gain regulatory approval to use the tests officially in outbreak situations.”

From the study

We note that a faint band was sometimes observed in no template negative controls, however, this faint band was clearly distinguishable from true positives, as demonstrated by ImageJ analysis of black pixel density. Such image analysis could be performed in field situations through the use of a lateral flow reader. We note that the faint test bands in the no template negative controls and Fig. 2 have been shown to disappear using higher dilutions of RPA product in the lateral flow device (e.g. 1:100–1:200) [48]

https://virologyj.biomedcentral.com/articles/10.1186/s12985-018-0985-8

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