Dog tag is an informal but common term for a specific type of identification tag worn by military personnel. The tags' primary use is for the identification of casualties; they have information about the individual written on them, including identification and essential basic medical information such as blood type and history of inoculations. They often indicate a religious preference as well.
A pair of blank dog tags on one ball chain
U.S. Army dog tags from World War II
ID tags for Lt. Henry Correll of the 2nd Vermont Volunteer Infantry
A World War I German army dog tag indicating name, place of birth, battalion, unit and serial number
A blood type is a classification of blood, based on the presence and absence of antibodies and inherited antigenic substances on the surface of red blood cells (RBCs). These antigens may be proteins, carbohydrates, glycoproteins, or glycolipids, depending on the blood group system. Some of these antigens are also present on the surface of other types of cells of various tissues. Several of these red blood cell surface antigens can stem from one allele and collectively form a blood group system.
A hospital worker takes samples of blood from a donor for testing
