Blood donation clinic. Hand of a man donating blood in a blood donation clinic, with medical workers in the background. 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 right). 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.