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20 Cards in this Set
- Front
- Back
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When do alloantibodies/ unexpected antibodies show up in a patient? (After what two processes?)
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Can form during some blood transfusions or can form during some pregnancies.
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Review: Primary immune response is via [ IgM / IgG ] and occurs within 10 days to 2 weeks.
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IgM
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Review: Secondary Immune response is via [ IgM / IgG ] and occurs within hours to 1-2 days and can be 100x greater than primary response since the body has already seen the antigen and it is ready to go.
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IgG
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Compare IgM and IgG with regards to:
A. structure: monomer, pentamer? B. does it cross the placenta? C. Is it made by the fetus? D. is it part of the primary or secondary immune response? E. what is the half life? F. does it bind complement? G. is hemolysis intravascular or extravascular? |
IgM: pentamer, does NOT cross placenta, IS made by the fetus, primary immune response, ~5 days, yes binds complement, intravascular.
IgG: monomer, yes crosses placenta, not made by fetus, secondary immune response, ~21 days, doesnt bind complement, hemolysis is extravascular |
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What is the most important aspect of transfusion?
A. matching the ABO blood group B. matching the Rh blood group C. screening for unexpected/ alloantibodies D. crossmatch compatability testing |
A. matching the ABO blood group
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ABO blood group genes are on which chromosome?
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chromosome 9
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Type ____ blood is the universal RBC donor and type ____ blood is the universal RBC recipient. Type ___ is the universal plasma donor.
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Type O blood is universal RBC donor since there are no antigens on its surface (thus the recipient's plasma status wouldn't matter), and type AB blood is both the universal recipient (since recipient doesn't have any antibodies in plasma). AB blood is also the universal plasma donor (since donor doesn't have any antibodies in its plasma).
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Explain how hemolytic disease of hte fetus and newborn occurs.
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An Rh- mother carring an Rh+ fetus will become exposed to the baby's D+ RBCs during delivery and will make anti-D. During subsequent pregnancies, this IgG antibody crosses the placenta and causes destruction of fetal RBCs. Baby can be born with hydrops fetalis due to severe anemia secondary to RBC hemolysis. RHIg is used to prevent HDFN.
Thus, save D- blood for women of childbearing age so they don't become immunized and put their future babies at risk. |
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What are examples of unexpected or alloantibodies?
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Anti Kidd, anti-Kell, anti Duffy, anti-D
Serum from patients who required transfusion is screened looking for antibodies formed in response to previous antigenic RBC exposure. |
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What is crossmatching compatibility testing?
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After you type and screen, you do crossmatching which confirms ABO type and final compatibility between patient serum and donor RBC. This is done prior to all RBC transfusions. You take the patient serum and add donor RBCs. If agglutinates, it is NOT compatible!
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The diract antiglobulin test (DAT) used to be called the Coomb's test. What is the reagent used?
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Anti-human IgG . those bridge the antibodies and cause them to agglutinate so they can be seen macroscopically. A positive DAT shows that RBCs are coated with antibody.
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What is an acute hemolytic transfusion reaction?
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WHen preformed patient antibody reacts with transfused RBC. Can be due to ABO error or other antibodies. Antigen-antibody complexes cause activation of kinins, coagulation, vasoactive amins, intravascular hemolysis. Severe hypotension, vascular constriction leading to renal failure and possibly death can also occur. Fever, chills, change in blood pressure, respiratory distress, flank pain, nausea, impending doom and change in urine color are also possible.
Delayed hemolytic transfusion reaction is also possible but is less severe and due to unexpected alloantibodies usually. |
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True or False:
Hepatitis C virus is the most common bloodborne pathogen and is a greater risk than HIV in transfusions. |
TRUE
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What component of blood is stored at room temperature and thus runs a risk of being contaminated with bacteria --> septic transfusion reaction?
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platelets
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True or False:
Immunomodulation is an adverse effect of transfusion due to infectious disease. |
FALSE, this is due to the transmission of active lymphocytes from the donor, impacting the recipient's own immune responsieness. The WBCs coming fromthe donor and other substances inthe plasma can also created an inflammatory process in the recipient.
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Whole blood transfusions are rarely done because though it would contain RBCs and stable clotting factors, they wouldn't contain _______ and labile clotting factors ____________ would dissipate in plasma with time.
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no platelets (due to storage necessity - platelets are stored room temp while whole blood is at much lower temps). Clotting factors V and VIII also dissipate with time.
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1 unit of RBCs should increase Hgb by _____ g/dL and Hct by ____%.
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1 unit of RBCs should increase Hgb by 1 g/dL and Hct by 3%
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What is cryoprecipitate and when should it be used?
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Cryoprecipitate is a byproduct that occurs when fresh frozen plasma is thawed. It is rich in FVIII, XIII, vW factor, fibrinogen, fibronectin. Since cryoprecipitate is rich in only VIII, XIII, vWF, fibrinogen and fibronectin, it is NOT used interchangeably with plasma; plasma is used to replace multiple coagulation factor deficiencies.
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What are signs of a transfusion reaction?
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Rise of 1C in temp, change in BP (either up or down), difficulty or changes in breathing, hives, rashes, erythema.
Can be due to: non-immune infectious: viral, bacterial, parasitic, new pathogens non-immune non infectious: circulatory overload, hypothermia, electrolyte changes, iron overload Immune- hemolytic: RBC ABO incompatibility, clerical check at bedside Immune- non hemolytic: fibrile non hemolytic transfusion reaction (regarding cytokine release from WBC), allergic transfusion reaction |
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Acute hemolytic transfusion reactions are usually caused by ____________ whereas delayed hemolytic transfusion reactions are usually due to __________.
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acute : clerical error
delayed: alloantibodies |
