Frances' Notes Flashcards
A and B alleles code for?
Glycosyltransferase enzymes that add sugar to H antigens for A and B antigen creation
Se and se
Codes for transferase enzyme the attaches fucose to create H antigen in secretions
A allele codes for?
Attaches N-acetyl-D-galactosamime to H antigen
B allele codes for?
Attaches D-galactose to H antigen
Copies of A1 allele on RBCS
1,170,000 - 810,000
Copies of A2 allele on RBCS
290,000 - 240,000
Other A subgroups
A3, Ax, Am, Ael
Anti A and Anti B antibody type
IgM
Anti A,B antibody type
IgG
When is allo- anti A clinically significant?
When it reacts at 37C
Anti-f
Compounded c and e haplotypes
Anti-G
Present with C or D, appears anti D and C which cannot be separated
Anti-Lw
Appears anti-D, usually an autoantibody distinguished with DTT
Needs interaction with Rh proteins to be expressed
Blue Top Tube samples may be used for?
ABORH testing only
Can adsorption cause RBC hemolysis?
Yes, if an antibody to an antigen present on the cell is absorbed it will cause the cell to lyse.
How long do you keep donor and recipient samples after testing?
One week after the transfusion, and ABO type and screen is valid for three days, meaning a maximum save time of 10 days.
What are the requirements of packed red blood cells to be used in an exchange transfusion?
CMV negative, preserved in CPDA – 1, less than five days old, irradiated, and sickledex negative
How can cold antibodies be removed to allow testing for alloantibodies to occur?
By using the pre-warmed technique to wash the cells, by adding DTT or 2ME to remove the antibodies
What is the difference between acquired B and B phenotype?
Acquired B is a transient condition caused by an infection, whereas B phenotype is a genetic condition inherited in an autosomal dominant pattern.
What is an amorph gene and what are some examples of this?
A nonfunctional gene, examples are le, se, and h
What antibodies do the Bombay phenotype make?
Anti-H, anti-A, and anti-B, and anti-Lewis as well
What antibody is commonly found in patients that received chronic or multiple transfusions?
Anti-S
What can developing anti-I cause, and how does that development begin?
Anti-I arises from a Mycoplasma pneumonia infection which can cause transient Cold Autoimmune Disease secondary to the infection
What types of hemolysis do ABO and Rh cause?
ABO antibodies cause intravascular hemolysis, Rh antibodies cause extravascular hemolysis
In HDN what should you test to determine what antibody is the cause?
The mothers plasma should be tested as it will contain the antibodies that are attacking the fetal cells
Why are platelets agitated during storage?
The agitation allows oxygen to enter the bag and keep the platelets viable as they need oxygen to survive
What kind of blood should be given to IgA deficient patients?
Generally they are given blood that has been frozen in glycerol, which requires the blood to be washed and deglycerized before transfusion
What are the expiration dates of “spiked” products?
Products kept at room temperature have a 4 hour expiration date, products that are refrigerated have a 24 hour expiration date.
What is the key marker for TACO and TRALI transfusion reactions?
A drop in O2 saturation due to lung injury or circulatory overload
What signs and symptoms does bacterial sepsis have?
An increase in temperature and a decrease in blood pressure
How can sickle cells be separated for testing?
The cell suspension is added to a hypotonic solution which will burst normal red cells leaving only the sickle cells behind for testing.
What are the requirements in labeling for blood and blood components?
Name of component Method of collection Preservative and anticoagulant Content or volume Number of units in a pooled component Sedimenting agent used in cytopheresis (hydroxyethel starch (HES))
What particular type of solution should not be infused to the same tubing as blood or components that contains citrate?
Lactated ringer’s solution or other solutions containing calcium
Can medications or other solutions be added to our infused through the same tubing as blood components?
No, with the exception of physiological saline, nothing may be added to the same tubing as this counts as modifying a pharmaceutical product
What conditions cause a unit to be discarded prior to issue?
A purple color in a RBC bag indicating bacterial contamination
A hemolyzed bag
Donor units that have positive DATs
If a unit is spiked before it’s expiration date and is then transfused can it still be used if it’s going to cross that expiration date?
Yes, but this is a rare exception
What are the components of AS?
Adenine, dextrose, sodium chloride, and monobasic sodium phosphate or mannitol
Should patients with TTP be given platelets?
The Thrombopoeitin will simply coat the new platelets and cause negative feedback
How is cryoprecipitate made?
By thawing FFP at 12 6°C recovering the precipitate via centrifugation and refreezing it within one hour
What are the expiration dates of thawed cryoprecipitate?
If thawed and not pooled it can be stored at room temperature for six hours, if pooled it may only be stored at room temperature for four hours
Calculating the cryoprecipitate dose
The number of cryoprecipitate bags required = the desired increase in FVIII level x the patients plasma volume / the average units of FVIII per cryoprecipitate
CCI calculation
(Post platelet count - pre-platelet count) x BSA/platelets transfused
A normal CCI should be greater than 5000 after transfusion
What are the acceptable amounts of leukocytes in leukocyte reduced platelets?
< 8 x 10^5 or < 5 x 10^6
What anticoagulant is used with apheresis platelets?
ACD-A
What is the concentration of granulocytes in a granulocyte transfusion?
> 1 x 10^10
They are also irradiated to remove lymphocytes but maintain neutrophils
