RT Journal Article
SR Electronic
T1 The effectiveness of clinical Influenza diagnosis in a Belgian out-patient setting identifies the need for rapid diagnostic assays
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP P4202
VO 42
IS Suppl 57
A1 Peter Van den Eede
A1 Lieselot Houspie
A1 Liesbeth Van Wesenbeeck
A1 Hanne Meeuws
A1 Lieven Stuyver
A1 Gabriela Ispas
A1 Marc Van Ranst
YR 2013
UL http://erj.ersjournals.com/content/42/Suppl_57/P4202.abstract
AB In primary care, influenza diagnosis is based on physical examination associated with diagnosis of Influenza Like Ilness (ILI) and/or Acute Respiratory Infection (ARI). Diagnosis is difficult as these symptoms are induced by several respiratory pathogens. This prospective study targets Belgian patients consulting their physician with ILI and/or ARI within the first 3 days of symptom onset. Recruitment and sample collection started at the peak of 2011-2012 influenza epidemic in Klein Brabant, Belgium. Patients were questioned using a study-specific questionnaire and mid-turbinate swabs were collected and stored at -20°C for later diagnosis of influenza A by RT-PCR.We recruited 177 patients with an average age of 37 years old. The majority visited their physician within 1 day of symptom onset. The PCR influenza A positivity rate was 56% (100/177) with a median Viral load (VL) of 6.99 log RNA copies/ml. The median VL declined from 7.5 log in patients presenting within 1 day to 5.4 log in patients presenting on day 3 after symptom onset. Despite the clear difference in VL between day 1 and 3, only a minor decline from 96% to 83% was observed in proportion of diagnosed ILI patients. Compared to the PCR results, ILI had a sensitivity of 95% (95/100), a specificity of 14% (11/77) and an accuracy of 60% (106/177). Overall, ILI was a poor indicator for influenza infections even during the influenza season. Given the fast intercept of Influenza patients after symptom onset and a median VL > 6 log during the first 2 days of symptoms, complementation of clinical diagnosis with rapid diagnostic tests can improve influenza diagnosis in primary care.