Blood inflammatory profile on admission was variable, with 13% of the children presenting with leukopenia and 6% with thrombocytopenia ( Table 2) . Respiratory samples collected to diagnose influenza A/ H1N1v infection were nasopharyngeal aspirates and nasopharyngeal swabs in 58% and 39% of the patients, respectively. Compared to PCR (considered as the gold standard), the sensitivity of antigen by RAT was low, being only 29% (10/34) and 57% (47/83) using Coris RespiStrip and Binax Now testing, respectively (data not calculated for DIF method, as only performed on 11 samples). The sensitivity of culture was quite better at 76% (107/141).