Patient blood is routinely tested to determine what blood type the patient has. Blood Types "A", "B", and "O" are the main types of blood. Blood typing tubes are used by clinical laboratories to determine the type of blood a patient has as well as to detect the presence of unexpected antibodies which may cause reactions with donor blood. Blood typing tubes are also used for blood compatibility testing which requires the clinical analytical testing of both patient and donor blood to ensure that the two blood samples are compatible in the event of a needed blood transfusion. Capitol Scientific offers a wide variety of blood typing tubes from various manufacturers in different sizes.