Blood donation. Nurse holding the hand of a man who is donating blood. A vein in the man's arm has been punctured with a needle (venepuncture) following the application of a tourniquet to the upper arm. The donor blood is being collected in a blood bag (lower centre). The blood will be separated into its component parts and used to treat various blood disorders, and to treat blood loss during surgery or after an accident. Photographed in Belgium.