Final answer:
Type O negative blood is used in emergencies due to its universal donor status, and agglutination with both anti-A and anti-B antibodies indicates an AB positive blood type.
Step-by-step explanation:
In a critical situation where a patient is experiencing severe bleeding and immediate blood transfusion is necessary, without time for blood type determination, type O negative blood is typically used for transfusion. This is because O negative blood is considered the universal donor and can be given to patients of any blood type without the risk of agglutination or immune reaction, as it lacks A, B, and Rh antigens.
In the scenario of the blood draw for a scheduled surgery, if both anti-A and anti-B antibodies cause agglutination in the patient's blood sample, this indicates that the patient's blood type is AB positive. This is a normal reaction for individuals with AB blood type, which means that their red blood cells express both A and B antigens on their surface.