[Values of clinical signs and rapid diagnostic test in the diagnosis of influenza A (H1N1) new variant in pediatric emergency department].

Aim Of The Study: To evaluate the values of clinical signs and the rapid diagnostic test (RDT) in the diagnosis of influenza H1N1 new variant in the pediatric emergency room.

Method: From 18 August to 1st December 2009, children admitted to the pediatric emergency department of CHU Nord (Marseille, France) and suspected of flu according to French guidelines, were tested for influenza using both an influenza RDT and a polymerase chain reaction (PCR) assay specific for H1N1. From 3 November to 3 December, clinical signs were also noted (fever, headaches, myalgia-arthralgia, shivers, diarrhea).

Results: A total of 1122 children were tested: 367 children (32.1%) had a positive specific PCR. The RDT value was: sensitivity 65.2% [55.8-73.6], specificity 99.5% [98.1-100], positive predictive value (PPV) 97.5% [91.8-100], negative predictive value (NPV) 91.2% [90.3-91.5], positive likelihood ratio (LRP) 153.7 [53.5-452.9] and negative likelihood ratio (LRN) 0.393 [0.387-0.411]. Clinical data were available for 504 children (328 over 2 years of age). In children more than 2 years of age and in multivariate analysis, headaches were the only sign significantly associated with a positive PCR (aOR=2.53 [1.25-5.12]). Overall, headaches and/or myalgia-arthralgia were valuable indicators for clinical diagnosis of flu, with a 75.8% NPV. Among children with a positive PCR, diarrhea was more frequent in children under 2 years of age (OR=2.76 [1.19-6.40]). The sensitivity of the RDT improved (90.9% [85.2-94.6]) when flu signs were also present.

Conclusion: Associating clinical signs and RDT for the diagnosis of influenza A (H1N1) new variant in a pediatric emergency room improves selection of children requiring appropriate antiviral treatment.