11 Sep New Rapid Flu Tests Are Simple, Fast and Accurate
MedicalResearch.com Interview with:
Jesse Papenburg, MD MSc FRCPC
FRQS Clinical Research Scholar
Assistant Professor of Pediatrics, McGill University
Div. of Pediatric Infectious Diseases, Dept. of Microbiology
Montreal Children’s Hospital
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Influenza viruses cause yearly epidemics of acute respiratory illness affecting 5 to 30 percent of the population. Diagnosing influenza on the basis of only clinical symptoms is difficult because its manifestations vary and are nonspecific. Reverse transcriptase polymerase chain reaction (RT-PCR) is the gold standard for flu diagnosis, but these tests must be sent to a laboratory and have turnaround times that extend beyond the clinical encounter. Rapid and accurate diagnosis of influenza has the potential to improve patient outcomes and decrease health care costs.
Since 2011, two novel classes of rapid influenza diagnostic assays i.e., with results available in <30 minutes, have been commercialized with claims of improved sensitivities based on technological improvements: 1) automated immunochromatographic antigen detection tests (digital immunoassays, DIAs) and 2) rapid nucleic acid amplification tests (NAATs).
Our systematic review and meta-analysis synthesized the available evidence and compared the diagnostic accuracy of commercially available rapid tests for the detection of influenza A and B infection:
- Overall, the rapid tests displayed very high specificities (≥98%). Physicians can therefore diagnose influenza with confidence on the basis of a positive RIDT, DIA, or rapid NAAT result.
- The pooled sensitivities for DIAs (80.0% for influenza A and 76.8% for influenza B) and rapid NAATs (91.6% for influenza A and 95.4% for influenza B) are markedly higher than those for RIDTs (54.4% for influenza A and 53.2% for influenza B).
MedicalResearch.com: What should clinicians and patients take away from your report?
Response: The diagnostic accuracy of the newer DIAs and rapid NAATs is far superior to that of traditional RIDTs; moreover, they are simple, fast, and approved for use at the point of care by non-laboratory personnel. The results of our study suggest that traditional RIDTs are likely to be phased out by regulatory agencies because of their poor sensitivity, especially in adults.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
- Similarly to a previous study from our group on Respiratory Syncytial Virus (RSV) rapid tests (Chartrand et al., J Clin Microbiol 2015), we found that studies that declared industry sponsorship in the form of funding or in-kind provision of study materials produced higher sensitivity estimates compared to non-sponsored studies. This underscores the importance of conducting and publishing independent evaluations of commercial diagnostic tests.
- Moreover, no NAAT studies in our review evaluated point-of-care testing and very few reported adult-specific data; therefore evaluations of NAATs in these settings are needed.
- Finally, additional clinical impact and cost-effectiveness analyses of DIAs and NAATs should help guide decisions about applying rapid testing for influenza in clinical practice.
MedicalResearch.com: Is there anything else you would like to add?
Response: This study was supported in part by the Quebec Health Research Fund and by an investigator-initiated study grant from BD Diagnostic Systems. Funding sources had no involvement in study design, conduct, analysis, or publication.
MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.
Merckx J, Wali R, Schiller I, Caya C, Gore GC, Chartrand C, et al. Diagnostic Accuracy of Novel and Traditional Rapid Tests for Influenza Infection Compared With Reverse Transcriptase Polymerase Chain Reaction: A Systematic Review and Meta-analysis. Ann Intern Med. [Epub ahead of print 5 September 2017] doi: 10.7326/M17-0848
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