BLOOD GROUPS & TYPING

Blood Groups RBCs contain antigens (glycoproteins) for cell recognition (identification tags) The immune system has cells and chemicals that can recognize proteins as non-self proteins, try to destroy or inhibit protein’s that are foreign to the person’s body. – 30 common varieties - over 100 "family antigens" – common antigens - ABO and Rh cause vigorous transfusion reactions – others mainly used for ID purposes (paternity, inheritance, etc. - only typed in cases of several transfusions (cumulative effect)

Blood Typing Blood cell marker proteins can cause a life threatening immune reaction, determining the presence of these proteins help lessen the possibility of tissue rejection or transfusion reaction.

Antigen A molecule that triggers an immune response.

Antibody A type of plasma protein produced by the immune system. Antibodies react with non-self markers (antigens)and try to destroy or inhibit them.

ABO blood groups – based on presence or absence of A or B antigens on RBCs – plasma antibodies act against antigens not present on that individual's RBCs – see chart

Antigens & Antibodies

Transfusion Reaction Mismatched RBCs antigens attacked by plasma antibodies agglutination of foreign RBCs can: – clog small BV - reduce blood flow – lysed RBCs release hemoglobin into blood-reduced oxygen capacity - blocks kidneytubules and causes renal shutdown Reactions: fever, chills, vomiting Treatment: alkaline fluids to dilute hemoglobin, diuretics to increase urine flow to flush kidneys

Agglutination

One type of antigen-antibody reaction is when the antigens are “glued” together with antibodies. This clumping (agglutination) is the reaction that happens during an incompatible blood type transfusion.

In the ABO system, blood is mixed anti-A serum and anti-B serum, serum is plasma with clotting factors removed. Anti-A causes agglutination when the A antigen is present. Anti-B contains antibodies that react with the B antigen.

Know the information contained in this chart

Rh factor (D antigen) Rh+ 85% of Americans - carry Rh antigen on RBC Rh- don't have antigen on RBC less severe transfusion reaction (hemolysis of donor RBCs) - doesn't usually occur until 2nd transfusion due to body's reaction time can cause erythroblastosis fetalis (hemolytic disease of the newborn) if Rh- woman carries Rh+ baby – 1 st baby is usually okay due to reaction time unless there was a bleeding problem during the pregnancy or a previous miscarriage or abortion. – 2 nd baby will have its blood cells attacked by mother’s antibodies- – Rhogam shot can prevent this if injected at 28 weeks of pregnancy and again right after birth.

Transfusions In case of blood loss, body tries to: – 1. reduce BV volume to maintain circulation to vital organs – 2. step up production of RBCs for replacement 15-30% loss - pallor & weakness over 30% - severe shock may be fatal substantial blood loss - whole blood transfusion Plasma, electrolyte solutions ( Ringer's solution) etc. can be used to increase blood volume while body steps up production of RBCs

Developmental Aspects Embryonic – Day 28 of pregnancy – RBC in fetal circulation – By 7 th month: red marrow is chief site of hematopoiesis – HbF – fetal hemoglobin Greater ability to pick up oxygen Replaced by HbA after birth Immature liver may lead to physiological jaundice

Developmental Aspects Adulthood – Dietary deficiencies or metabolic disorders cause abnormalities in BC formation or hemoglobin production – Iron deficient anemia more common in women

Developmental Aspects Old age – Leukemia risk – Pernicious anemia Stomach mucosa atrophies with age Less intrinsic factor (located in lining of stomach – function is B12 absorption) Less B12 absorption Leads to pernicious anemia

Diagnostic Blood Tests low hematocrit = anemia high fat level (lipidemia) = problems with heart disease blood glucose test – diabetes, hypoglycemia, hyperglycemia differential WBC indicates type of infection platelet count – thrombocytopenia – clotting problems complete blood count = CBC – see handout

Formed Elements Blood Type – Determined by presence or absence of specific antigens (agglutinogens) on outside surface of RBC – Antigens are called A, B, and Rh – Antibodies (agglutinins) in plasma react with foreign antigens on RBCs RBCs clump and break open – Anti-Rh antibody made after exposure to Rh- positive blood cells Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Formed Elements Blood Types and Cross-Reactions Figure 11-7(a)

Figure 11-7(b) 1 of 5 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Surface antigens Opposing antibodies + + Agglutination (clumping) and hemolysis

Figure 11-7(b) 2 of 5 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Surface antigens

Figure 11-7(b) 3 of 5 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Surface antigens Opposing antibodies + +

Figure 11-7(b) 4 of 5 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Surface antigens Opposing antibodies + + Agglutination (clumping)

Figure 11-7(b) 5 of 5 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Surface antigens Opposing antibodies + + Agglutination (clumping) and hemolysis