H1N1 pandemic shed light on ineffectiveness of some viral diagnostics

ARLINGTON, Va. — The 2009 H1N1 pandemic allowed a unique opportunity to review viral diagnostic testing for influenza. Depending on the diagnostic method, clinicians should remember that performance may vary depending upon the patient’s age, test type, laboratory, or issues with specimen collection and transport, according to Richard L. Hodinka, PhD.

“The pandemic highlighted the good, the bad, and the ugly in viral diagnostics,” Hodinka, of The Children’s Hospital of Philadelphia, said during a presentation at Infectious Diseases Society of America’s Seasonal and Pandemic Influenza Meeting, held here. “The pandemic has really taught us from a diagnostic standpoint that we can do better.”

Because the accuracy of an influenza diagnosis on the basis of symptoms alone is unreliable, diagnosis requires the help of the laboratory and must be rapid and reliable to have a significant effect on patient care and management, he said.

Hodinka presented an overview of issues associated with the diagnosis of influenza. Culture-based assays and rapid diagnostic tests are two of the most commonly used assays and were considered the gold standard in the past. However, Hodinka said molecular testing is the new gold standard for detecting influenza and other respiratory viruses because of their high sensitivity and specificity.

“Molecular testing is now widely recognized, and manufacturers are motivated to develop fully automated, simple molecular systems. The relevance of traditional methods is now being questioned,” he said.

Some of the advantages of using this type of test include: compatibility of expense, labor and time; the ability to detect coinfections; and quick turn-around times. Yet, Hodinka said there are some concerns:

Few available, but many in the pipeline.
Lack of point-of-care molecular technology for rapid results in clinics, ED, physician offices.
How fast and how often can testing be done?
Is the diagnosis of coinfections relevant?
Does detection of nucleic acid always correlate with transmission and disease?
Does the benefit outweigh the cost?

Despite these concerns, Hodinka said advances in molecular technology will be seen soon.

“Pandemics allowed us a unique opportunity to utilize our labs. Like all diagnostic tests, evaluate influenza tests in the context of available clinical and epidemiologic information. We need to remember that regardless of the method, performance can vary,” he said.

For more information:

Hodinka RL. Presented at: the IDSA’s Seasonal and Pandemic Influenza Meeting; Jan. 27-28, 2011; Arlington, Va.

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