CALCA and acute respiratory distress syndrome: In the 21 patients with MODS (all in the severe group), the median levels of serum ferritin, PCT, and CRP were 33,070 ng/ml (range 20,691–99,800 ng/ml), 4.13 ng/ml (range 0.26–56 ng/ml), and 49.4 mg/l (range 8.78–127 mg/l), respectively; in the 19 patients with ARDS (all in the severe group), the median levels of serum ferritin, PCT, and CRP were 18,511 ng/ml (range 10,550–99,800 ng/ml), 5.0 ng/ml (range 0.02–82.92 ng/ml), and 55.89 mg/l (range 5.02–145 mg/l), respectively.