ASCP MLT Immunohematology

A ficin (enzyme) treated panel can be a useful tool for determining the identity of an antibody. On a ficin-treated panel, reactions with ____________system are enhanced, while reactions with __________system are degraded and reactions with ___________ stays the same (unaffected).

(Rh, Lewis, Kidd) (MN, Duffy) (Kell)

A pregnant female who was injected with RhIg antenatally has a positive antibody screen at delivery. The antibody has been confirmed as anti-D and reacts only in the indirect antiglobulin test. Many laboratory consider reaction strength to be an indicator of whether the anti-D is likely passive or immune. To be considered probably passive, an anti-D reaction strength is typically less than or equal to which reaction grade?

2+

Platelets should be stored at that temperature?

20-24C

What is the basic technique employed to detect antibodies with a commercial set of panel cells?

Indirect antiglobulin test An antibody panel utilizes the IAT principle as the reagent RBC are detecting antibodies present in the patient serum or plasma for identification.

You are working at a blood donor center; the date is July 1st. A unit of packed RBCs expired on August 4th. If the unit of blood is irradiated, what will be he new expiration date?

July 29th - because after irradiation, the expiration date shortens to 28 days from the date of expiration, or the original expiration date, whichever is first.

While ABO, Rh, Kell, Duffy, Kidd, SsU are clinically significant, which of the following antibodies generally react at only the Coombs phase (aka AHG phase)

Kell, Duffy, Kidd ABO, Rh, and SsU react at both IS and 37 phase as well.

What symptoms of HDFN does phototherapy help prevent?

Kernicterus. Phototherapy helps prevent kernicterus by chemically altering the bilirubin in the surface capillaries to harmless substances that can be excreted. Kernicterus is associated with severe cases of jaundice.

Delayed hemolytic transfusion reactions are usually caused by antibodies directed against what blood group system?

Kidd

Which of the following antibodies is known to result in severe hemolytic transfusion reactions, but is not always detected during pre-transfusion testing in the blood bank?

Kidd Kidd is the most common cause of delayed transfusion reactions. The antibody titer for Kidd can drop to undetectable levels several months after primary exposure to the antigen. Upon subsequent exposure to the antigen, a robust antibody response and hemolysis of the offending donor red cells occurs. This is also referred to as an anamnestic response.

Bacterial contamination is MOST likely in what blood products?

Platelets

An urticaial transfusion reaction is characterized by:

Rash, itching, and hives

Which of the following actions should take place if a donor experiences numbness in the mouth during an apheresis procedure?

Reduce the flow rate

All of the following criteria for donor RBC to be used for an exchange transfusion relate to both ABO HDFN and HDFN due to anti-D: Less than or equal to 7 days old (or fresher) Reconstituted with AB FFP CMV negative Negative for hemoglobin S Irradiated T/F

True

The Kleihauer-Betke test used to quantitate FMH has poor reproducibility. T/F

True

The incidence of HDFN due to anti-D varies significantly according to race and ethnicity. T/F

True

Which of the following is the most common type of autoimmune hemolytic anemia?

Warm autoimmune hemolytic anemia 60-70%

If Jka is showing dosage, how might reactions on a antibody panel appear?

Weaker if heterozygous for Jka and Jkb

The cause of the most severe life-threatening hemolytic transfusion reactions is:

anti-A, anti-B, anti-A,B

Why would a unit of group O blood never be administrated to a Bombay patient?

anti-H in recipient

When performing transfusion reaction investigation, what is the clinical check used to detect?

Errors that may cause an ABO-incompatibility due to patient or donor unit mix up

Hemoglobinuria and hemoglobinemia will present in reactions where there is extravascular hemolysis. T/F

False. In extravascular hemolysis, there is no release of free hemoglobin. Sensitized red cells are removed from circulation by the monocytes and macrophages in reticuloendothelial system.

What other component(s) can be shipped together with FFP?

Frozen RBC's and CRYO

What types of whole blood would be the least satisfactory to transfuse to a type AB patient?

Group O. Group O whole blood contains both anti-A and anti-B which could react with the recipient's RBCs.

What additional information is required on a label or tie tag of an autologous unit?

Identification of the recipient

A secondary immune response is generally associated with what antibodies?

IgG

Anti-K, anti-Jka

IgG antibodies

Which of the following antibodies is predominantly associated with the secondary antibody response:

IgM

Anti-M. anti-I

IgM antibodies

When a unit of packed RBC's is split using the open system, each half-unit must be issued within:

24 hours

Rh immune globulin is manufactured to be capable of neutralizing ___________ mL of Rh positive whole blood.

30

he appropriate dosage of Rh immune globulin (RhIg) to administer post-delivery to an Rh-negative mother delivering an Rh-positive child is calculated based on the estimated volume of fetal bleed. What is the value of x in the formula given below that is used to calculate RhIg dosage? Number of vials of 300 µg RhIg = volume of fetal bleed/x mL

30 A 300 µg vial of RhIg can prevent immunization to a fetomaternal hemorrhage (FMH) of 30 mL of D-positive whole blood. Using the estimated volume of fetal bleed determined by the Kleihauer-Betke test or flow cytometry, the number of vials of RhIg (300 µg) to inject is calculated as follows: Number of vials of 300 µg RhIg = volume of fetal bleed/30 mL. In the interests of safety some American organizations recommend the following to deal with decimal points: If the number to the right of the decimal point is <5, round down and add 1 vial (e.g., 1.4 = 1 +1 = 2 vials) If the number to the right of the decimal point is greater than or equal to 5, round up and add 1 vial (e.g., 1.7 = 2 +1 = 3 vials).

An issued unit of blood may be returned to blood bank inventory if it has not been outside a monitored refrigerator for longer than:

30 minutes If, for instance, transfusion is delayed, a unit of blood must be returned to a temperature-monitored refrigerator within 30 minutes to maintain the integrity of the blood cells.

How many micrograms (ug) of IgG anti-D are in a 1500 IU vial of RhIg?

300 The conversion rate is one ug = 5 IU

Platelets that are not collected by an apheresis method must be prepared within ____________ of the collection of whole blood.

8 hours

Units of A-, B-, and O-negative red blood cells are shipped to your transfusion service. What testing MUST be performed by tour facility prior placing these units into your inventory?

ABO and Rh

At what phase of antibody screen testing is it most important to read the reactions in order to detect clinically significant antibodies?

AHG IS reading would detect IgM antibodies primarily. These are not considered clinically significant if reacting at IS only. A reading at 37C may show if a clinically significant antibody is causing hemolysis.

Which procedure used to obtain a fetal blood sample to monitor severity of HDFN can also be used to deliver intravenous transfusions? A. Amniocentesis B. Cordocentesis C.Doppler sonography

B. Cordocentesis Aka percutaneous umbilical blood sampling or PUBS.

Which of the following blood components contain the most factor VIII concentration per ml? A. plasma B. cryoprecipitate C. fresh frozen plasma D. platelet concentrate

B. cryoprecipitate

Which of the following is the MOST liely discrepancy seen when a person demonstrate an "acquired B-like" phenomenon? A. Forward B, reverse O B. Forward AB, reverse A C. Forward O, reverse B D. Forward B, reverse AB E. Forward AB, reverse B

B. Forward AB, reverse A Acquired B is seen only in a subpopulation of group A1 individuals. The individuals that demonstrate acquire B possess anti-B does not react with the acquired B antigen; consequently, the auto control is negative.These patients should be transfused with group A or O blood.

When should a prewarm technique be performed? A. If you suspect a warm autoantibody B. If you suspect a cold antibody C. If you suspect multiple IgG antibodies

B. If you suspect a cold antibody Prewarming of a sample with suspected cold antibody will prevent he activation and binding of the antibody at room temperature. Warm autoantibodies are not affected by prewarming. IgG antibodies react at 37C since that is the optimum reaction temperature.

When performing an antibody screen, both the screen cells are 4+ at immediate spin and W+ at AHG. The antibody panel shows 4+ reactions at immediate spin and W+ reactions at AHG and there is no specific match to the reaction pattern. The auto control is negative. What would be a logical next step? A. Have patient redrawn B. Repeat testing using warmed patient sample and reagents and just do AHG reading C. Run an enzyme panel

B. Repeat testing using warmed patient sample and reagents and just do AHG reading Phase of reactivity is primarily at immediate spin (4+) and reactions get weaker at AHG (w+). There is no specific pattern of reactivity and the auto control is negative which rules out an autoantibody. This is a strong cold antibody which is still slightly present after incubation and washing. Activation and binding of the antibody takes place at room temperature or colder. Eliminating this phase will prevent the antibody from binding. Cold antibodies usually are more of a nuisance to blood bankers and are not clinically significant.

During a routine inspection, a unit of unexpired blood was noticed to have a black color with numerous small clots. What is the likely cause for this observation?

Bacterial contamination Bacterial contamination can manifest itself in several ways including: the presence of clots, darker purple-black color of blood unit, until can appear cloudy, hemolysis may be present.

Which of the following statements is NOT true about the Lewis blood group: A. antigen expression is influenced by secretor status B. antigens are adsorbed onto the red cells from the plasma C. antigens are a structural component of the red cell membrane D. ABO group affects antigen expression

C. antigens are a structural component of the red cell membrane Lewis antigens are not a component of the red cell membrane, in fact, are not produced by the red cell at all. They are adsorbed from the plasma.

All of the following cellular antigens are important to an immunohematologist except: A. blood group antigens B. histocompatibility antigens C. haptens D. autoantigens

C. haptens A hapten is an incomplete antigen.

An aliquot of AS-1 red blood cells is being prepared from an intact packed cell unit using a sterile connection device. During the process of preparing an aliquot, the sterile device fails and blood drips onto the counter from the product tubing. What should be done with the primary unit?

Change the expiration date to 24 hours The unit can be used within 24 hours so long as the unit itself has not been compromised.

RBC with positive DAT cannot be tested accurately with blood typing reagents that require an indirect antiglobulin technique unless they have bee treated with __________ to dissociate IgG from the RBC membrane.

Chloroquine diphosphate Ficin ZZAP

Which of the following blood components will provide the best source of fibrinogen for a patient with hypofibrinogenemia:

Cryoprecipitate Cryoprecipitate is the cold-insoluble protein remaining after FFP is thawed slowly at 1-6 degrees Celsius. It contains about 50% of the factor VIII, and 20-40% of the fibrinogen present in the original fresh plasma. It also contains some factor XIII, and Von Willebrand factor.

A group A Rh positive infant born to a group O Rh negative woman has a 1+ positive DAT. The mother had a negative antibody screen at delivery and received antenatal RhIg. Which of the following are possible causes of the newborn's positive DAT? A. Anti-A B. Passive anti-D C. Antibody to a low frequency antigen D. All of the above are possible causes E. None of the above are possible causes

D. All of the above are possible causes Anti-A is possible because the mother is group O and the newborn is group A. Passive anti-D is possible because the mother received antenatal RhIg and the infant is D+. An antibody to a low frequency antigen is possible because the mother's antibody screen is negative and antibody screen cells are not usually positive for rare antigens.

Which of the following blood group antigens are most susceptible to destruction by the action of enzymes: A. Rho B. Jka C. Lea D. Fya

D. Fya Duffy, and Fya and Fyb antigens, are most sensitive to enzyme treatment since they will be destroyed during this process.

Which of the following antigens is classified as a Major Histocompatibility Complex Class II antigen (MHCII)? A. HLA-A B. HLA-B C. HLA-C D. HLA-DR

D. HLA-DR HLA-A, HLA-B, and HLA-C are all class I MHC.

Which of the following is responsible for causing graft-versus-hosy-reactions? A. Platelets B. Granulocytes C. Monocytes D. Lymphocytes

D. Lymphocytes 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.

An individual with type AB blood will demonstrate the complete absence of which of the following antigen sites? A. A B. B C. H D. None of the above

D. None of the above H antigen is a precursor to the ABO antigens.

When AHG or Coombs serum is used to demonstrate that red cells are antibody coated in vivo, the procedure is termed:

DAT (direct antiglobulin test)

Which of the following blood group antigens is not expressed, or only weakly expressed on cord blood cells? A. K B. Jka C. M D. Leb E. ABO

Leb Newborns are phenotypically Le(a-b-)

A patient with two or more documented febrile nonhemolytic transfusion reactions (FNHTRs) should receive ______________ blood component.

Leukoreduced

HLA-A and HLA-B antigens can be detected using which of the following techniques?

Lymphocyte cytotoxicity HLA-A and B antigens are detected by mixing the lymphocytes being tested with known HA antisera and complement and then measuring the cell lysis (leukocytotoxicity) that occurs.