Validity of a clinical model to predict influenza in patients presenting with symptoms of lower respiratory tract infection in primary care

Background. Valid clinical predictors of influenza in patients presenting with lower respiratory tract infection (LRTI) symptoms would provide adequate patient information and reassurance. Aim. Assessing the validity of an existing diagnostic model (Flu Score) to detect influenza in LRTI patients. Design and Setting. A European diagnostic study recruited 1801 adult primary care patients with LRTI-like symptoms existing ≤7 days between October and April 2007–2010. Method. History and physical examination findings were recorded and nasopharyngeal swabs taken. Polymerase chain reaction (PCR) for influenza A/B was performed as reference test. Diagnostic accuracy of the Flu Score (1× onset