DNA test for viral infections 'highly accurate'

Researchers in the USA have developed a blood test that relies on genetic information from patients' immune systems to distinguish between viral and bacterial infections.

The test looks for a genetic 'signature' of activity in 30 genes that are turned on during a viral infection. Lead researcher Dr Aimee Zaas of Duke University told Bloomberg Businessweek the test worked like a freeze-frame to show 'what those genes are doing at the moment in time it's captured'.

A small preliminary study of the test in a real world setting was published in Science Translational Medicine. Among 102 people arriving at a hospital's emergency department with fever, 28 had a viral infection, 39 had a bacterial infection and 35 were healthy controls.

The test provided true positive identifications of viral infection for 25 of the 28 cases, and correctly ruled out the negative cases 94 percent of the time.

Although further evaluation of the test would be necessary before it could be considered for widespread clinical use, Dr Zaas said her team was 'very pleased that the assay could pick out those with viral infection with a high degree of accuracy'.

Current methods of distinguishing the two types of infection can take several days, whereas Duke University's DNA test delivers results in only 12 hours. Quicker diagnosis would enable doctors to prescribe suitable treatments faster to patients and also help avoid unnecessary antibiotic use.

Antibiotics are often used in a trial-and-error fashion or as first-line therapy when the nature of the infection is unclear, despite this practice being increasingly discouraged.

And over-prescription of antibiotics can have serious public health consequences, co-senior author, Dr Chris Woods underlined: 'One of the big global threats at the moment is the emergence of bacterial resistance, and that is largely driven by overuse of antibiotics'.

'A tool that enables us to accurately identify viral infections could curb the indiscriminate use of antibiotics and reduce the development of resistant pathogens'.