Improved rapid molecular testing may become available in office setting

NEW YORK — Rapid molecular tests for viruses and other infections may soon become widely available and could help with decisions regarding antibiotics, according to a presenter here at the 26th Annual Infectious Diseases in Children Symposium.

Gregory A. Storch, MD, director of the division of pediatric infectious diseases and pediatric laboratory medicine at the Washington School of Medicine, discussed the history of diagnostic virology and the rapid shift to molecular testing. Molecular and diagnostic tests are available for an array of viruses, including respiratory, gastrointestinal, and mucocutaneous/genital using blood and urine samples, and many more are on the way.

Gregory A. Storch

Currently available tests

Because multiple infections are relatively common in children, with rhinovirus being the most common, the rapid turnaround time with molecular testing also helps facilitate clinical and infection control decisions. This type of testing also is able to detect antiviral resistance mutations, according to Storch.

Storch reviewed a few of the available tests that will help “guide the road to the future,” he said. These include the GeneXpert test, which is simple to perform and sensitive for a broad range of enteroviruses. Results of the test are usually available within 2.5 hours, making diagnosis quick. However, it does not detect parechoviruses.

Respiratory virus multiplex assays are able to detect multiple agents in the same sample and several assays are licensed for detection of influenza A/B and respiratory syncytial virus. Other multiplex assays can detect some or all of the following: influenza A/B, influenza A(H1), influenza A(H1 2009), influenza A(H3), parainfluenza virus (1-4), adenovirus, human metapneumovirus, and rhinovirus coronavirus (OC-43, 229E, NL63, HKU1). Turnaround time for these tests is 1 to 8 hours, depending on the assay, Storch said.

The BioFire FilmArray Respiratory Panel can give results within 60 minutes; however, the instrument only accommodates one sample at a time.

Tests in development

Storch said some tests currently in development are being designed for quick and easy use because these types of tests are desperately needed in the developing world and areas with limited resources.

“However, the very same characteristics that would make a test useful in a developing world are the same characteristics that would make a test useful in the office,” Storch said during the presentation.

In the future, most testing will be molecular with an emphasis on assays that are simple, sensitive, single or multiplexed and rapid, he said. Multiplex testing will include both viral and nonviral pathogens. Information from human genes may be incorporated into the testing.

“If I can look into the future, one of the ways we may overcome the quandary of overdetection of asymptomatic viruses is to add on detection of human genes that are indicative as to whether the patient is reacting to a bacterial infection, a viral infection, or both," Storch said.

High throughput sequencing will allow new pathogen discovery, recognition of new strains, enhanced detection of antiviral resistance and recognition of virulence determinants.

For more information:

Storch G. Presented at: IDC NY 2013; Nov. 16-17, 2013; New York.

Disclosure: Storch reports being on the advisory boards for Roche Molecular Diagnostics and BioFire, being a consultant for Meridian Biosciences and has had research conducted in his lab for Luminex, Meridian and Nanosphere.