A newly developed paper test strip can detect different influenza types and may be able to be identify avian and swine flu strains, potentially guiding both clinical care and disease surveillance efforts, according to a study published in the Journal of Molecular Diagnostics.

Researchers from Princeton University and the Broad Institute of the Massachusetts Institute of Technology and Harvard University collaborated with the US Centers for Disease Control and Prevention on the project. 

The inexpensive, one-step test strip uses CRISPR gene-editing technology to distinguish between influenza A and B and subtypes H1N1 and H3N2. With further development, the test strip could be reprogrammed to distinguish between SARS-CoV-2 and flu and recognize swine flu and avian flu, including the H5N1 subtype currently causing an outbreak in US dairy cattle, the study authors said. 

The team tested the strip using 20 nasal swabs from people with flu-like symptoms during the 2020-2021 flu season, nasal fluid from healthy people as the control, and 2016-2021 influenza sequences downloaded from the National Center for Biotechnology Information Influenza database. They compared the results with those from quantitative reverse transcription-polymerase chain reaction (RT-PCR) tests.

High hopes for point-of-care testing

Paper strip test results of nasopharyngeal samples showed 100% agreement with those of the more expensive and resource- and time-intensive RT-PCR tests. The test can identify two target viruses at the same time, which can help distinguish between flu strains susceptible or resistant to the antiviral drug oseltamivir (Tamiflu).