According to ROC statistics IL-33 levels, which are assessed at admission and exceed the cut-off value of 4.77 pg/mL, they accurately identify 71.8% of polytraumatized patients developing ARDS, whereas 75.7% of the individuals with an initial IL-33 level lower than 4.77 pg/mL are expected not to suffer from ARDS. This evidence concerns the gene IL33 and acute respiratory distress syndrome.