RESUMO
BACKGROUND: The clinical diagnosis of influenza is difficult in the younger children. OBJECTIVES: Evaluate the impact of rapid influenza diagnostic test (RIDT) on clinicians' estimation of the clinical probability of influenza in children. STUDY DESIGN: This prospective study included children aged from 1 month to 5 years who were admitted in a university paediatric emergency department during an influenza epidemic period and presented with fever without source. The RIDT Quickvue(®) was performed on nasopharyngeal aspiration and results were confirmed with immunofluorescence and/or PCR. The clinical probability of influenza and serious bacterial infection (SBI) was evaluated for each child before and after the physician(s) was informed of the RIDT results. RESULTS: 170 children were included from January 15th through March 18th, 2013. After the only clinical examination, the overall clinical probability of influenza was 66.0% [CI 95%: 63.04-68.4], and was significantly increased at 92.4% [CI 95%: 89.5-95.3] in case of positive RIDT and significantly decreased at 30.8% [CI 95%: 29.0-32.5] in case of negative RIDT without knowing the results of laboratory tests. Whereas the initial clinical probability of influenza were appropriate regarding the prevalence (66.0% vs. 57.0%), the probability of SBI was overestimated (30.2% vs. 8.8%). The RIDT result positive enabled a significant decrease in orders for chest X-rays (64,4% vs. 45.8%, p<0,05) and laboratory tests (71,1% vs. 41.1%, p<0,05). CONCLUSIONS: The RIDT seems to be a useful diagnostic tool for ED clinicians in epidemic conditions. Improving clinician estimation of flu probability would reduce orders for imaging and testing.