Calprotectin as a postoperative marker after colorectal resections for infections compared to CRP (C-reactive protein), PCT (procalcitonin), lactate and leukocytes

Interventions: Group 1: On the day of the reconnaissance, the blood sampling with CRP, leukocytes, PCT, lactate and calprotectin. The next blood samples (CRP, leukocytes, PCT, lactate and Calprotectin) are performed on the 1st, 3rd and 5th postoperative day. Primary outcome(s): How does the calprotectin level in the serum behave pre- and post-operatively after a colon / rectum resection? Study Design: Allocation: ; Masking: ; Control: ; Assignment: ; Study design purpose: prevention