Transcript BLOOD GROUPS & TYPING - Randolph High School

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
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
– 1st baby is usually okay due to reaction time unless there was a
bleeding problem during the pregnancy or a previous miscarriage
or abortion.
– 2nd 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
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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 7th 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
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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 Rhpositive blood cells
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Formed Elements
• Blood Types and Cross-Reactions
Figure 11-7(a)
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Surface
antigens
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Opposing
antibodies
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Agglutination (clumping) and hemolysis
Figure 11-7(b)
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Surface
antigens
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 11-7(b)
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+
Surface
antigens
+
Opposing
antibodies
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 11-7(b)
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+
Surface
antigens
+
Opposing
antibodies
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Agglutination (clumping)
Figure 11-7(b)
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+
Surface
antigens
+
Opposing
antibodies
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Agglutination (clumping) and hemolysis
Figure 11-7(b)
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