Final answer:
In blood typing, agglutination in the presence of anti-A and anti-B antibodies indicates an AB blood type. Over about an hour in a glass tube, blood clots, separating out serum for analysis. In emergencies, O negative blood is transfused as it is the universal donor type.
Step-by-step explanation:
The question asked by the student pertains to the determination of blood type during a blood typing test. When the technician adds anti-A antibody and anti-B antibody to the patient's blood and both samples visibly agglutinate, this is a normal response that indicates the patient has AB blood type. This blood type is characterized by the presence of both A and B antigens on the surface of the red blood cells. Therefore, there is no error made by the technician in this scenario.
In another scenario presented, a lab technician collects a blood sample in a glass tube and allows it to sit for approximately one hour before harvesting serum. During this time, the blood has had time to clot, and the liquid portion that can be separated is called serum. This serum is free from blood cells and clotting components and can be used for further analysis.
The subject of blood transfusion in an emergency scenario, where the patient's blood type cannot be determined, the hospital would transfuse O negative blood. This blood type is considered the universal donor and is generally safe to be used in critical situations because it lacks A, B, and Rh antigens, preventing adverse reactions in most patients.