Final answer:
In a critical emergency following a motor vehicle accident with no time for blood type testing, Type O negative blood is transfused to the patient, as it's universally compatible. If a blood sample agglutinates with both anti-A and anti-B antibodies, it indicates that the patient has Type AB blood.
Step-by-step explanation:
According to the Guidelines for Field Triage of Injured Patients, a patient who has been in a motor vehicle accident with multiple traumatic injuries and severe bleeding that's critical in nature should be transported to a trauma center providing the highest level of care within the trauma system. In such emergency situations where there is no time for blood type determination, the type of blood transfused is Type O negative. This is because O negative blood is considered the universal donor type and can be given to patients of any blood type without causing an immune response or agglutination.
In the context of preparing for a scheduled surgery, if a patient's blood sample agglutinates with both anti-A and anti-B antibodies, this is a normal response for someone with Type AB blood, indicating the presence of both A and B antigens on the surface of their red blood cells.