Transfusion of RBC is associated with post operative infections. Our hypothesis is that stored blood could be related with increased post operative infection risk. Surgical patients transfused during the operation or immediately after will be included in our study. Patients will receive fresh or old blood during the whole recovery.

Inclusion Criteria:

• Patients transfused during or in 24h after surgical operation

Exclusion Criteria:

• Patients transfused during the 30 days before the operation
• Immunodepressed patients
• Infections during the 30 days before operations
• Emergency surgery