BLOOD BANK
Which unit contains the proper number of platelets from a random donor? The correct answer is highlighted below 3.8 x 1010 4.0 x 1010 4.5 x 1010 5.8 x 1010
5.8 x 1010 Feedback Platelet concentrates are required to have a minimum of 5.5 x 1010 platelets/unit. Random donor platelet concentrates typically contains between 5.5 and 8.5 X 1010 platelets suspended in about 50 mL of plasma. This is approximately 70% of the platelets which were present in the original unit of whole blood collected by the donor.
The Kleihauer-Betke test is based on the principle that red cells containing fetal hemoglobin are more susceptible to acid elution than cells containing adult hemoglobin. True/False
FALSE Feedback The opposite is true. The Kleihauer-Betke test is based on the principle that red cells containing adult hemoglobin are more susceptible to acid elution than those containing fetal hemoglobin.
Which of the following immunoglobulins is capable of fixing complement by the classical pathway: A. IgG, IgA B. IgM, IgA C. IgG, IgM D. IgG, IgD
Feedback IgG1, IgG3, and IgM fix complement via the classical pathway. IgA fixes complement through the alternative pathway. Only IgG crossed the placental barrier.
Which specific terminal sugar causes a red cell to have A antigenic activity? A. Galactose plus glucose B. Galactose C. N-acetylgalactosamine D. Glucose
Feedback Once substance H is developed, the addition of the sugar N-acetylgalactosamine to the terminal position of the chain gives the molecule "A" antigenic activity.
A solution of gamma globulins containing anti-Rh (D) is given to an Rh (D) negative mother to: A. Prevent fetal cells from initially sensitizing the mother B. Neutralize any of the child's antibody that may have passed the placental barrier C. Neutralize any natural maternal antibodies present D. Prevent greater antibody response in a previously sensitized mother
A. Feedback Gamma globulin (anti-D) is given to Rh-negative mothers to prevent any D antibody production, which could cause harmful effects in future pregnancies with an Rh-positive fetus. The administered anti-D will bind fetal Rh-positive cells that may come from the fetus in vivo; therefore the mother will not produce anti-D herself, preventing sensitization.
Which of the following best describes the direct antiglobulin test principle: A. AHG detects antibody already coated to red cells B. AHG prevents antibody from coating red cells C. AHG is directed against cell antigens D. AHG is directed against plasma antibodies
A. Feedback In the DAT, or direct antiglobulin test, AHG is added to patient cells without the addition of antisera. This means that if a positive reaction occurs, it is due to the presence of already sensitized red blood cells which had a coating of antibody in vivo.
Which type of blood component is most implicated in bacterial contamination? A. platelets B. red cells C. plasma D. cryoprecipitate E .all of the above
A. Feedback Platelets are the most common product implicated in bacterial contamination cases. This is because the room temperature storage requirement provides an adequate environment for bacterial growth.
If an autologous blood donor weighs 35 kg, how much blood can be collected for later transfusion? A. 315 mL B. 340 ml. C. 360 ml. D. 380 ml. E. 450 ml
A. 315 mL Feedback Volume to draw = (Donor's weight in kilograms / 50 kg (minimum weight requirement) x 450 mL (volume of unit to be donated) In this case, Volume to draw = (35 kg / 50 kg) x 450 mL = 315 mL
After the second spin in the preparation of platelets from whole blood, the platelet products should be: A. Allowed to rest for 1-2 hours. B. Agitated vigorously for 3 hours C. Pooled immediately and microwaved D. Frozen
A. Allowed to rest for 1-2 hours. Feedback After the second spin in the preparation of platelets, the platelet bag should be allowed to rest at room temperature for 1 - 2 hours. The platelet component is placed on a rotator to resuspend the platelets that have aggregated during the centrifugation process, but should not be vigorously agitated. They should remain at room temperature, not pooled and heated in a microwave, and not frozen.
What component is indicated for patients who receive directed donations from immediate family members to prevent transfusion-associated graft versus host disease (TA-GVHD)? A. Irradiated Red Blood Cells B. Washed Red Blood Cells C. IgA-deficient products D. HLA matched products
A. Irradiated Red Blood Cells Feedback Gamma-irradiation of blood components containing viable lymphocytes is very effective in preventing TA-GVHD. Irradiation is recommended for all Whole Blood, Red Blood Cell, Platelets, and Granulocyte transfusions to patients at risk. Patients at risk include neonates less than 4 months, patients with an acquired or congenital immunodeficiency, or patients receiving a directed donation from a family member . Irradiation prevents proliferation of donor lymphocytes with a required dose of 25 Gy to the mid plane of the blood container and a minimum of 15 Gy elsewhere.
Which of the following antibodies can be enhanced using enzyme panels during antibody identification in the blood bank? A. Rh B. Lewis C. Kidd D. Duffy E. Lutheran F. Kell
A. Rh B. Lewis C. Kidd Feedback The Rh system antibodies along with Lewis and Kidd blood group antibodies can show an enhanced reaction when analyzed with enzyme treated panels. The antibodies which can be destroyed or weakened by enzyme treated panels are: the MNS group (though s can be variable), Duffy, and Xga.
For which of the following antibodies is the DAT most likely to be negative when testing a newborn for possible HDFN? The correct answer is highlighted below A. anti-A B. anti-c C. anti-D D. anti-K E. anti-Fya
A. anti-A Feedback The DAT is most likely to be negative in ABO HDFN. It's possible that the washing done as part of the DAT may break the bonds between anti-A (or anti-B) and the newborn's poorly developed A (or B) antigens.
Which of the following group B antigens is generally associated with a mixed field reaction: A. B B. B3 C. Bm D. Bx
B. B3 Feedback B3 is characterized by a weaker than usual reaction with anti-B and by a mixed field reaction with the same reagent.
Which Lewis antigen(s) will be exhibited on the red cells of adults who have the Le, Se, and H genes? A. Lea B. Leb C. both Lea and Leb D. neither Lea or Leb E. Se and H
B. Leb Feedback Inheritance of both Le and Se genes produces the Leb antigen on red blood cells. The Se gene codes for the enzyme, a-2-L-fucosyltransferase which adds L-fucose to the type 1 precursor H (type 1). The Le gene codes for another L-fucose which forms the Leb antigen. Some of the precursor chains are not affected by the Se gene and, therefore, form the Lea antigen. Hence, it is possible to see both Lea and Leb in the plasma and secretory fluids. However, only Leb adsorbs onto the red cells of adults (most likely due to competitive binding), causing them to phenotype Le(a-b+).
A mother's serologic results are shown above. Her newborn types as group A Rh positive with a (1+) positive direct antiglobulin test (DAT). Which of the following investigative tests would be most useful to resolve the cause of the positive DAT and should be done FIRST? A. Test an eluate prepared from newborn's red cells against an antibody identification panel by IAT. B. Test newborn's plasma against group A1 red cells and group O antibody screen cells by IAT. C. Test newborn's plasma against mother's red cells by IAT. D. Test newborn's plasma against father's red cells by IAT.
B. Test newborn's plasma against group A1 red cells and group O antibody screen cells by IAT. Feedback The mother is group O Rh positive with a negative antibody screen and the infant is group A Rh positive. Results are consistent with a possible case of AB HDFN. The most useful follow-up would be to test the infant's plasma against A1 red cells and group O antibody screen cells (as a control), expecting only the A1 cells to be positive if the DAT was due to ABO incompatibility.
Which of the conditions listed below must be met before a unit of Red Blood Cells that has been issued and returned can be reissued? The correct answer is highlighted below A. The unit has an attached temperature indicator. B. The container has a tamper-proof seal and the seal remains unbroken. C. Although not attached, segments are still available for recrossmatching. D. The blood has been stored continuously at 1-10°C.
B. The container has a tamper-proof seal and the seal remains unbroken. Feedback The correct answer is B. There must be a tamper proof seal and the seal cannot be broken. Regarding the reissue of blood, 21CFR640.2 states: Blood that has been removed from storage controlled by a licensed establishment shall not be reissued by a licensed establishment unless the following conditions are observed: The container has a tamper-proof seal when originally issued and this seal remains unbroken. A segment is properly attached and has not been removed, except that blood lacking a properly attached segment may be reissued in an emergency provided it is accompanied by instructions for sampling and for use within 6 hours after entering the container for sampling. The blood has been stored continuously at 1 to 6° C and shipped between 1 and 10° C. The blood is held for observation until a significant inspection* can be made. While the temperature of the unit during storage should be between 1 and 6° C, it is not a requirement that a temperature monitoring device is attached to the unit. There must be a segment attached to the unit that could be used for crossmatching unless it is an emergency situation and there are special instructions sent with the unit. *If the color or physical appearance is abnormal or there is any indication or suspicion of microbial contamination the unit must not be issued for transfusion.
Which D variant has a qualitative difference in the D antigen that allows individuals with the D variant to produce anti-D? Select all that apply. A. weak D B. partial D C. partial weak D D. None of the listed D variants have a qualitative difference in the D antigen
B. partial D C. partial weak D Feedback Both partial D and partial weak D have a qualitative difference in the D antigen that allows individuals with the D variant to produce anti-D to the D epitopes that they lack.
Which of the following antigens are well developed on fetal cells? A. Lewis B. ABO C. Kell
C. Kell Feedback Antigens develop at various rates both in utero and after birth. Kell is an antigen that is well-developed on fetal cells, ABO is slightly weaker, and Lewis is either poorly developed or not present at all on fetal cells.
Which one of the following blood group systems may show a cell typing change during pregnancy? A. Rh B. MNS C. Lewis D. Duffy E. D mosaic
C. Lewis Feedback The Lewis group antigen, Lea may disappear during pregnancy, resulting in the formation of anti-Lea antibodies. The majority of these antibodies are IgM and clinically insignificant.
Rh immune globulin therapy in postpartum women provides: A. Long term protection B. Antibody blocking C. Passive protection D. Active immunity
C. Passive protection Feedback Protection against alloimmunization is only for the recent pregnancy. There is of course no long term protection against the development of Rh antibodies if the patient is exposed again in the future.
Which one of the following tests BEST correlates with the severity of hemolytic disease of the newborn (HDN). A. Rh antibody titer of baby's blood B. L/S ratio C. amniotic fluid bilirubin D. antibody titer of mother's blood
C. amniotic fluid bilirubin Feedback Amniotic fluid bilirubin is increased in association with the severity of hemolytic diseases of the newborn. As red blood cells lyse during these conditions, bilirubin builds up as a byproduct of the red cell destruction. The more red blood cells that are being destroyed in the baby, the more increased the bilirubin level will become.
What should be the first step performed to resolve a case where all forward and reverse ABO typing results are negative on a patient? A. Wash the patient cells and retest. B. Get a new sample and retest. C. Test the patient cells with Anti-H Lectin. D. Incubate all testing tubes at 22ºc
D. Incubate all testing tubes at 22ºc Feedback If all results for a patient's forward and reverse type are negative, it is suggested that the reactions incubate at room temperature for at least 15 minutes to help strengthen any reactions to become observable.
Which of the following is responsible for causing graft-versus-host reactions: A. Platelets B. Granulocytes C. Monocytes D. Lymphocytes
D. Lymphocytes Feedback Graft-versus-Host reactions are caused by the engrafting of immunocompetent T lymphocytes into a severely immunosuppressed recipient. They can be prevented by gamma irradiation of cellular blood components.
The rheumatoid factor in rheumatoid arthritis is PRIMARILY which type of immunoglobulin?
IgM Feedback Rheumatoid Factor (RF) is an antibody against the Fc portion of IgG molecules. It is primarily, of the IgM class and can less commonly be IgG or IgA. These circulating antibody complexes are found in the synovial tissue and synovial fluid and tend to cause systemic problems. In the laboratory, routine latex agglutination test would typically detect only IgM RF since most IgG and IgA antibodies are non-agglutinating.
In performing an AHG test it is important to completely wash the red cells in order to:
avoid neutralization of the anti-human globulin serum Feedback Inadequate cell washing will lead to unbound antibody remaining in the red cell suspension. This residual unbound antibody would be available to neutralize the AHG (Coombs serum) so it will not react with red cells bound with antibody.
