Transfusion medicine Flashcards
What are RBC antigens also reffered to as?
agglutinogens
What type of antigens does Type O blood contain?
Type O contains neither A nor B antigens
List the frequencies of blood type and RH factors
Blood Groups Frequency (%) Type O 47 A 41 B 9 AB 3
Rh factor
Rh– 15
Rh+ 85
When are antibodies formed against the RBC antigens not present in the individual?
In the first year of life
What agglutinins are present in type A blood?
anti B
What blood type is a universal donor?
O
What blood type is a universal recipient?
AB
What components are immediately separated when a blood donation is given?
Fresh frozen plasma (FFP)
Packed red blood cells (PRBCs)
granulocytes
platelets
Which minor blood fractions are pooled from multiple blood donors?
albumin
gamma globulin
cryoprecipitate
fibrinogen
Within 24 hours after donation blood is devoid of?
normally functioning platelets and some clotting factors.
specialized storage and transfusion techniques optimize the survival and availability of each component.
What are packed RBCs?
Most plasma is removed
Contains the same red cell mass as 1 unit of whole blood at half the volume and twice the hematocrit
How much does 1 unit of PRBCs raise the hemoglobin and hematocrit?
One unit raises the hematocrit 3% in an adult, or increases the hemoglobin by 1 g/dL on average
What are washed RBCs?
Removes leukocytes, platelets, and proteins, and reduces the titer of anti-A and anti-B antibodies, permitting safer transfusion of type O PRBCs in non-O recipients
When are WRBCs used?
Used to prevent allergic reactions in IgA-deficient patients
Used in patients who have had febrile (nonhemolytic) reactions to previous transfusions as a result of leukocyte antibodies or IgA sensitization
When are Leukocyte reduced RBCs used?
Used to reduce likelihood of febrile reactions, immunization to leukocytes, and disease transmission
Used in patients who are chronically transfused, potential transplant recipients, and those with more than one febrile transfusion reaction in the past.
How much of the US blood supply is leukocyte reduced?
Currently about 60-75% of U.S. blood supply is leukoreduced
What does irradiation do to donated RBCs?
Irradiation destroys the donor lymphocytes’ ability to respond to the host’s foreign antigens
What risk do irradiated RBCs reduce?
Reduces the risk of graft vs. host disease in susceptible patients
When are irradiated RBCs used?
Used for bone marrow transplant donors or recipients, directed donations from family members, and patients with cellular immune deficiency
What is compatibility matching or cross referencing?
The donor’s RBCs and serum are mixed with the recipient’s RBCs and serum to identify the potential for a transfusion reaction from minor antigens not recognized by ABO and Rh typing
Endpoint is the presence of RBC agglutination or hemolysis
A cross match test is done on a donor and recipient blood. The resulting mixture clumps. Is the blood compatible or not?
Not compatible
Do plasma products need to be cross matched?
Plasma products do not need to be crossmatched but should be ABO compatible because WBCs and platelets have ABO antigens.
What is a direct Coombs test?
Done on a sample of RBCs from the body to detect antibodies that are already attached to RBCs. Can be antibodies from the patient or those received from a blood transfusion
When is a direct Coombs test done in regards to a newborn baby?
Done on a newborn baby with Rh+ blood whose mother was Rh-. Tests whether the mother made antibodies and if the antibodies moved through the placenta to the baby.
What does a negative direct Coombs test mean?
The blood does not have antibodies attached to the RBCs
What does a positive Direct Coombs test mean?
the blood has antibodies that fight against RBCs. Could be caused by a transfusion of incompatible blood, hemolytic anemia, SLE, hemolytic disease of the newborn, lymphoma, mycoplasma infection, advanced stage cancer, infectious mononucleosis
What is an Indirect Coombs test?
Done on a sample of serum to detect antibodies present in the blood stream but not attached to RBCs. May lead to problems in a transfusion if mixing occurs.
What does a negative Indirect Coombs test mean when done for a transfusion?
Means the donor blood is compatible with the recipients.
What does a negative Indirect Coombs test mean when done for Rh- pregnant woman?
She has not developed antibodies against the Rh+ blood of the baby, so Rh sensitization has not occurred.
Other blood tests done on donated blood?
hepatitis B surface antigen hepatitis B core antigen hepatitis C antibody syphilis HIV testing antibody 1 and 2 HIV antigen HTLV 1 testing liver hepatocellular enzyme (ALT)
When should RBCs be given?
Given to raise the Hct level in patients with anemia or to replace losses after acute bleeding episodes
At what levels of Hgb and Hct is a transfusion recommended?
Transfusion recommended in patients with uncompromised cardiovascular function with Hgb < 7 or Hct < 21, or in patients with cardiovascular disease, sepsis, or hemoglobinopathy with Hgb < 10 or Hct < 30
How is a transfusion given?
Given through a large bore IV to minimize hemolysis and ensure rapid infusion of fluid
All blood and blood products are given through an appropriate filter.
Blood should be rewarmed at the time of administration to prevent hypothermia.
Monitor for transfusion reactions
Transfusion rate for hypotensive patients?
In a hypotensive patient, one unit may be given at 20 ml/kg/hr.
What is the transfusion rate for a patient in hypovolemic shock and continued hemorrhage?
there is no limit to the transfusion rate
At what counts should platelets be given?
Given prophylactically for counts < 10,000.
Also given for counts < 30,000 with bleeding or a minor bedside procedure, for counts < 50,000 and intra- or post-operative bleeding, for counts < 100,000 and bleeding post cardiopulmonary bypass
When should you not give platelets?
Do not infuse in thrombotic thrombocytopenia purpura or heparin induced thrombocytopenia
What is the usual dose of platelets and how much does 1 unit contain?
Usual adult dose is 6-10 units and can be infused rapidly (1 unit/10 min). One unit (pack) of platelets raises platelets by 5,000 – 10,000. Platelet concentrates contain most of the platelets from 1 unit of blood in 30-50 ml of plasma.
How is fresh frozen plasma (FFP) prepared?
FFP is prepared by separating plasma from the cellular components and rapidly freezing to preserve the coagulation factors
When is FFP indicated?
Given in patients with bleeding with an INR > 2
Also given in patients with a bedside procedure and an INR > 2, prophylaxis (no bleeding at time of administration) with INR > 6, thrombotic thrombocytopenia purpura, Coumadin reversal when indicated, bleeding with DIC, and massive transfusion cases.
When is FFP not indicated?
Not indicated for INR < 1.5.
What is cryoprecipitate used for?
Used as a source of fibrinogen and Factor XIII
When is cryoprecipitate given?
Give when bleeding occurs in the setting of dysfibrinogenemia, fibrinogen < 100 mg/dL, von Willebrand disease
What is the mode of action for Recombinant activated factor VII
It binds to the surface of activated platelets to activate factor X, which complexes with factor V leading to a thrombin burst and clot formation
What is Recombinant activated factor VII used to treat?
Used to treat patients with acquired factor VIII and IX inhibitors and for patients with congenital factor VII deficiency
What is factor VIII concentrate used to treat.
Prepared for treatment of hemophilia A
What are the administration guidelines for Factor VIII concentrate?
Administer 1 unit per kg body weight to increase factor VIII activity by 2-2.5%.
Factor VIII levels should be increased to 20-40% of normal for minor bleeds (small joints), 40-60% for moderate bleeds (large joint, neck, oral cavity), and 60-100% for life threatening bleeds (intracranial, intraabdominal, pharyngeal)
What is factor IX concentrate used to treat?
Used in treatment for hemophilia B
What is Recombinant activated factor VII used to treat?
Used to treat patients with acquired factor VIII and IX inhibitors and for patients with congenital factor VII deficiency
