Diagnosing Ebola in Minutes

Researchers from Harvard Medical School (HMS), Partners In Health, and Boston Children’s Hospital. New test for Ebola, successful in field trial. Published in The Lancet, this could be a game-changer for treatment, containment.

The new test can accurately diagnose Ebola virus disease within minutes at the point of care. This would give clinicians on-the-spot information to treat patients and contain or prevent outbreaks. New, commercially developed rapid-diagnostic test performed at bedside. Found to be as sensitive as the conventional laboratory-based method.

Lab-based test was the one used for clinical testing during recent Sierra Leone outbreak. West African Ebola epidemic has slowed since peak last fall.

Still 24 confirmed cases of Ebola reported in Guinea and Sierra Leone in the week of June 14. 

First step in fighting Ebola:

• Determine which patients are sick with the disease and which have other illnesses that look similar
• Current molecular approach:
  • laboratories must be built
  • samples of highly infectious blood must be drawn
  • often with unsafe needles and syringes
  • then shipped elsewhere putting more people at risk
• clinicians and patients must wait several days for results
• Delay in diagnosis and treatment

Simplifying the process and speeding up diagnosis could be very beneficial. Team at HMS started developing diagnostic tools to enable clinicians to diagnose Ebola patients quickly last year. One candidate: ReEBOV Antigen Rapid Test, developed by Corgenix, which seemed like a promising tool.

Worked with colleagues in Sierra Leone, to train local technicians to perform the test and help collect data for the study. The field trial took place at two treatment centers operated by the Ministry of Health and Sanitation of Sierra Leone.

160 patients suspected of having Ebola were tested during February 2015 using the rapid diagnostic test performed on a fingerstick blood sample at the point of care. The patients were also tested using the standard RT-PCR performed on plasma in the laboratory.

Results:

• The rapid diagnostic test detected all confirmed cases of Ebola that were positive by the benchmark test
• sensitivity of 100 percent
• identified all patients with Ebola found by the benchmark method

Both tests failed to detect a small number of Ebola cases that had been detected by an alternative lab test

• This test was more sensitive
• Not available for wide-use
• All cases had very low levels of the virus
  • More research is needed to assess how the new rapid diagnostic test will perform in patients still in the early stages of Ebola
• The ReEBOV test uses a drop of blood from a fingerstick performed with a safety lancet
  • Lancet prevents accidental needlesticks after the blood is sampled
    • Sample is applied to a treated strip, and if the sample is positive for Ebola, a colored line appears on the strip at a specific location