Exam IV Flashcards
Which blood group system is associated with resistance to malaria?
Duffy
Which antibodies are considered cold agglutinins?
N, P1, Ii
Which autoantibody specificity is associated with paroxysmal cold hemoglobinuria and what test is used to detect it?
P antigen, Donath-Landsteiner test
What procedure might help to distinguish between an anti-Fya and an anti-Jka?
enzyme treatment; Jka will be enhanced
Which blood group is produced in the tissues?
Lewis
What is the McLeod phenotype?
recessive mutation of the Kell system, characterized by the absence of the XK protein on the X-chromosome
What antibodies require the antiglobulin test (AHG phase) for in vitro detection?
Kell, Duffy, Kidd, Ss, Ii (with polyspecific)
What is the rarest phenotype of the Lutheran system?
Lu(a-b-)
Which antigen is X-linked?
Xga
Which antibody is often found in patients with infectious mononucleosis, lymphoproliferative disease, and cold agglutinins?
anti-i
Which antibodies are known for causing delayed HTR?
Kidd, anti-P1 (rare)
Fy(a-b-) is found primarily in which population?
African-American
Which antigen is found primarily in South, Central, and North American Indians and Asians?
Dia
Which blood group systems are known for showing dosage?
MNSs, Kidd, Lutheran, Duffy, Rh (Cc, Ee)
What is the most common antibody seen in the blood bank other than ABO and Rh?
anti-K
Which blood group antigen increases in strength as a newborn grows older?
Ii
Which genotype can immunize a patient with blood group Ss?
ss
Which antigens are actually white cell antigens that are expressed in variable degrees on red cells and can cause confusing reactions in serological testing?
Bg
Which antigens are well-developed at birth, susceptible to enzymes, and generally saline reactive?
Duffy
What are three common antibodies most likely to react at 37*C?
anti-C, anti-D, anti-E
What is the most practical manner of preventing transmission of malaria through blood transfusion?
permanent deferral from donating blood if you have ever been diagnosed with malaria or have ever been to an area where the disease is prevalent
Can unused autologous donations be placed in the general supply and used for a patient other than who it was intended for?
no
What is plasmapheresis?
process by which blood is drawn, plasma is removed and the remaining components are returned to the donor from whom they were taken
What is cytapheresis?
process by which blood is drawn, the cells are removed, and the remaining components are returned to the donor from whom they were taken
What is plateletpheresis?
process by which blood is drawn, platelets are removed, and the remaining components are returned to the donor from whom they were taken
Why should donor units be tested for weak-D?
weak-D positive units are considered to be Rh+ and should only be given to Rh+ patients
What are the two terms used to refer to AHG that contains both anti-complement and anti-IgG?
broad spectrum, polyspecific
A transfusion that replaces approximately a patient’s entire blood volume within a 24-hour period is called what?
exchange transfusion
What is an emergency release?
a physician signs an order for uncrossmatched blood products and accepts full responsibility for the transfusion of these products
What are homozygous cells used for “ruling out”?
antibodies that demonstrate dosage
Why should a patient’s serum/plasma for compatibility testing be stored?
in case the testing needs to be repeated
Leukocyte antibodies are usually responsible for what type of transfusion reaction?
transfusion-related acute lung injury (TRALI)
Which blood bank test detects in vitro sensitization?
IAT (indirect Coomb’s)
How is the shelf life of blood determined?
the preservative it is stored in, the temperature it is stored at, whether the hermetic seal has been broken or if the product has been pooled, whether or not it has been irradiated
What is the purpose of the albumin or LISS portion of an antibody screen or crossmatch?
reduces the zeta-potential to enhance the reaction
What information does a +DAT convey?
the patient’s red cells are being coated with IgG antibody and/or complement in vivo (inside the body)
What kind of transfusion reaction is a patient who has received multiple transfusions most likely to have?
febrile non-hemolytic transfusion reaction (FNHTR)
What does CPDA stand for?
citrate-phosphate-dextrose-adenine
What is the shelf like of a blood unit contained in CPDA-1?
35 days
What is the shelf like of a blood unit contained in AS-1?
42 days
How often should a new recipient sample be collected if a series of transfusions are to be administered over a period of several days?
no more than three days before each transfusion
Incomplete antibodies usually belong to which immunoglobulin class?
IgG
What does it mean to perform a major crossmatch?
patient serum/plasma is tested against donor red cells for compatibility
How many time are cells washed in an antibody screen, and what is the purpose of doing this?
3-4 times to remove any unbound IgG or other unbound protein that can possible interfere with testing
What is therapeutic phlebotomy and for what conditions can it be used?
the removal of blood as a means of treating a disease state; used for conditions such as polycythemia vera and hemachromatosis (iron overload)
What is the Rule of Three and why is it used?
when identifying an antibody, there should be three cells + for the suspected antibody and three = cells that do not contain the suspected antibody; this provides statistical confirmation
Explain an antibody screen, including why and when it is done, what the stages are, what happens if it is positive, and why there is a control.
performed using three different screening cells, usually alongside blood typing, and if a crossmatch is +, to determine if a potentially clinically significant antibody might be present in the patient plasma; if the screen is positive, a full antibody panel must be done to identify the specific antibody/antibodies; autocontrols are performed to rule out the possibility of autoagglutinins
What is a directed/specific donation?
blood, typically donated by a friend or family of the recipient, that is compatible with and specifically for a particular recipient
What blood group system does anti-Dia correlate to?
Diego
What blood group system does anti-Sc2 correlate to?
Scianna
What blood group system does anti-Xga correlate to?
Xg
What blood group system does anti-Cob correlate to?
Colton
What blood group system does anti-Ch3 correlate to?
Chido/Rodgers
What blood group system does anti-Ge3 correlate to?
Gerbich
If an antibody panel is performed and all cells are positive, including the control, what is the most likely explanation?
cold or warm autoantibody, or multiple antibodies
