Faster, More Sensitive Flu Diagnostics Developed

Influenza ultrastructure illustration (Dan Higgins, CDC)

Researchers at the RIKEN Omics Science Center in Yokohama, Japan have developed a new technique to identify influenza virus infection in only 40 minutes and with 100 times the sensitivity of conventional methods. The findings from the team led by RIKEN Omics’ Toshihisa Ishikawa appear in the online journal PLoS ONE.

Ishikawa and his colleagues conducted the research and developed the technique in 2009 and 2010 to come up with better ways of diagnosing pandemic flu. The 2009 pandemic influenza A(H1N1) virus spread quickly around the world, resulting in some 18,000 deaths. In Japan, the virus affected no less than 16 percent of the population.

The technique, called the RT-SmartAmp assay, detects the virus from patient swab samples. The researchers succeeded in combining tests of two genomic indicators — reverse transcriptase and isothermal DNA amplification reactions — in one step. This achievement also did away with the need for separate RNA extractions and polymerase chain reactions. Adding a fluorescent primer enabled the team to detect in about 40 minutes the hemagglutinin (HA) gene in the virus, which a RIKEN Omics team had analyzed in an earlier study.

The researchers tested the RT-SmartAmp method in clinical research at clinics and hospitals in Tokyo and Chiba, Japan from October 2009 to January 2010, where the new technique outperformed standard diagnosis tests in both speed and sensitivity. Of 255 clinical samples, more than half (140 or 55%) were identified as 2009 pandemic A(H1N1)-positive by RT-SmartAmp, compared to less than half (110 or 43%) detected by standard diagnostics. In nearly three-quarters (73%) of all 140 infection-positive cases, the RT-SmartAmp assay detected the presence of the pandemic influenza virus within 24 hours of fever onset.

Read more: National Lab, University to Certify Flu Screening Machine

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