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Updated: May 17, 2026

Rapid Molecular Detection and Differentiation of Influenza Viruses A and B
Published on: January 30, 2017
Diagnosis of influenza from lower respiratory tract sampling after negative upper respiratory tract sampling
Isaac I Bogoch1, Jason R Andrews, Kimon C Zachary
1Divisions of Internal Medicine and Infectious Diseases, Toronto General Hospital, Toronto, ON, Canada. Isaac.Bogoch@uhn.ca
Abstract:
In this retrospective cohort study, we demonstrate that PCR-confirmed diagnoses of influenza were made solely by lower respiratory sampling in 6.9% of cases, as traditional upper respiratory tract tests were negative, indeterminate or not performed. Clinical features of these cases are presented. Clinicians should consider lower respiratory tract sampling in select cases of influenza-like illness for diagnosis.
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