The levels of the vWF-cleaving protease ADAMTS13 antigen (0.54 IU/ml vs. 0.57 IU/ml; P = 0.58) and activity (0.38 vs. 0.37 IU/ml, p = 0.80) did not differ between patients with severe/necrotizing AP and mild AP. This evidence concerns the gene ADAMTS13 and alkaline phosphatase measurement.