Blood Typing Lab: Understanding Blood Compatibility

Biology Blood Typing Lab Experimental Question How do you determine which blood type is suitable to be donated or received in a blood transfusion? Introduction and Background: Humans can have the A, B, AB, or O blood type. The phenotypic differences are due to proteins anchored in the red blood cell (RBC) membrane and in the blood plasma. The proteins anchored on the red blood cells act as antigens and the proteins in the plasma act as antibodies. For example, type A blood has A antigens on the surface of the red blood cells and B antibodies (anti-B) in the blood plasma, whereas type B blood has B antigens on the surface of the red blood cells and A antibodies (anti-A) in the blood plasma. Type AB blood is unique because it has both A and B proteins on the surface of the red blood cells, but no plasma antibodies. Type O blood is equally unique because it has no antigens on the surface of the red blood cells, but has both A and B antibodies in the blood plasma. Blood type A Antigen on Red Blood Cell (RBC) A Antibodies in plasma B (Antibody-B), B AB O B A, B None A (Antibody-A) None A (Antibody-A) and B (Antibody-B) Mixing blood types has serious consequences. For example, when type A blood is mixed with type B blood, the antigens on the type A red blood cells react with the plasma proteins of type B blood. This antibody-antigen reaction causes severe clumping (agglutination) of the red blood cells. Agglutination tends to block blood vessels, resulting in brain and kidney damage and, ultimately, death. Those with type O blood are called universal donors. Although blood type O contains plasma proteins against blood types A, B it can be used in emergency transfusions as a donor to A, B, and AB blood types since the proteins in this blood plasma become so diluted in the recipient’s plasma that the amount of agglutination does not reach lethal levels. The O blood cells are not attacked by the anti-A and/or anti-B in the recipient because the O cells do not contain any A or B antigens. Those with type AB blood are called universal recipients since they have no plasma antibodies to react with the antigens found on A, B, and O types of red blood cells. Procedure: 1. With each blood sample, mix a few drops with the Anti-A, Anti, B and solutions, which contain the antibodies that bind to the respective antigen proteins. 2. Each blood sample should be tested with separate antibody solutions, so you will test each blood type for the A, and B proteins independently. 3. Check for agglutination (clumping) and record below for positive (agglutination) or negative (no agglutination) reactions. 4. Based on your results note the blood type of each individual. 5. Determine which blood types each patient could receive as a transfusion. Data: Patient 1 Testing Solution Antibody-A Antibody-B Reaction Blood Type (Clumping?) Possible Blood Type(s) for Transfusion Patient 2 Testing Solution Reaction Blood Type (Clumping?) Possible Blood Type(s) for Transfusion Reaction Blood Type (Clumping?) Possible Blood Type(s) for Transfusion Reaction Blood Type (Clumping?) Possible Blood Type(s) for Transfusion Antibody-A Antibody-B Patient 3 Testing Solution Antibody-A Antibody-B Patient 4 Testing Solution Antibody-A Antibody-B Conclusions: 1. How do you determine which blood type is suitable to be donated or received in a blood transfusion? 2. Explain why a blood transfusion must match a patient’s blood type. 3. A and B blood are codominant, if two parents with AB blood have a child, what possible blood types would you expect? 4. O blood is recessive to AB blood. What possible blood types could result from parents with O and AB blood? 5. Assuming all blood types are equally common, people with what blood types would have the best and worst odds of finding a donor?