Blood bank exam 2 (chapter 5, 8,9,10)

8 The indirect antiglobulin test detects which antigen - antibody reactions ? In vivo In vitro Both in vivo and in vitro None of the above

In vitro

What is a positive DAT? In vitro sensitization of RBC with antigen In vitro sensitization of RBC with antibody In vivo sensitization of RBC with antibody In vivo sensitization of RBC with antigen

In vivo sensitization of RBC with antibody

In interpreting an antibody screen, which of the following questions might be asked to decipher the class of antibody? Is the autologous control positive or negative? Is hemolysis present? In what phase did the reaction occur? Is rouleaux present?

In what phase did the reaction occur?

What will happen to I antigen expression when ABH sugars are removed from red blood cells? Increased expression Decreased expression No effect None of the above

Increased expression

How does LISS enhance antibody detection in the antibody screen? Increases the incubation times, which increases the sensitivity of the test Increases the zeta potential, promoting agglutination of sensitized red blood cells Increases the rate at which antibody binds to red blood cell antigens None of the above

Increases the rate at which antibody binds to red blood cell antigens

Which of the following is not involved in the Kell blood group system? Jsa K Kpb Jka

Jka

Why is it relatively easy to find compatible units for a patient with anti-K? Kell is a low-frequency antigen. Kell is a high-frequency antigen. Anti-K does not react at 37°C. Anti-K has a low avidity for its respective antigen

Kell is a low-frequency antigen.

What is tested in an antibody screen? Patient red blood cells are tested against group O reagent screening cells. Patient serum is tested against group AB reagent screening cells. Patient serum is tested against group O reagent screening cells. Patient serum is tested against group A reagent screening cells

Patient serum is tested against group O reagent screening cells.

Why is rouleaux not usually found in the AHG phase of antibody screens? High protein molecules are not reactive at 37°C. Patient cells are washed away before adding AHG. Patient serum is washed away before adding AHG. None of the above

Patient serum is washed away before adding AHG.

13 How is a 40 : 1 ratio of serum to cells prepared for the AHG test ? 5 drops of serum + 1 drop of a 5 % v / v RBC suspension 1 drop of serum + 1 drop of a 5 % v / v RBC suspension 2 drops of serum + 1 drop of a 5 % v / v RBC suspension 1 drop of serum + 5 drops of a 5 % v / v RBC suspension

2 drops of serum + 1 drop of a 5 % v / v RBC suspension

3 Why are check cells added to all negative reactions in the AHG test ? A To ensure AHG was not neutralized by free globulin molecules B To wash away any unbound antibody C To increase the cell - to - serum ratio D To bring the antibody closer to the antigen in the test system

A To ensure AHG was not neutralized by free globulin molecules

What is an elution? A technique used to dissociate IgM antibodies from sensitized RBCs A technique used to dissociate IgG antibodies from sensitized RBCs A technique used to reduce the zeta potential enhancing antigen binding None of the above

A technique used to dissociate IgG antibodies from sensitized RBCs

What might a positive antibody screen and a negative auto control indicate? An alloantibody is coating donor cells after a transfusion An autoantibody has been detected An alloantibody has been detected Drug-induced antibody reacting with patient cells

An alloantibody has been detected

1 Why is incubation omitted in the direct AHG test ? A Polyspecific AHG contains a higher dose of anti - IgG . B Incubation will cause lysis of red blood cells . C Incubation elutes complement components from red blood cells . D In vivo antigen antibody complex is already formed .

D In vivo antigen antibody complex is already formed .

What is the most common Kidd phenotype in the black population? Jk(a+b-) Jk(a+b+) Jk(a-b+) Jk(a-b-)

Jk(a+b-)

What is the ISBT designation for the Lutheran blood group system? LN LU LT LR

LU

What is the final step in antibody identification? Phenotype donor's RBC units for corresponding antigen Phenotype patient's RBCs for corresponding antibody Phenotype patient's RBCs for corresponding antigen Phenotype RBC units for corresponding antibody

Phenotype patient's RBCs for corresponding antigen

What screening cells are used primarily for testing donor units for unexpected antibodies? Pooled 2-vial 3-vial 4-vial

Pooled

Where are the Duffy antigens found? Red blood cells Platelets Lymphocytes All of the above

Red blood cells

Where are the Kell blood group antigens found? Red blood cells Platelets Lymphocytes All of the above

Red blood cells

Why is it important for screening cells to be from individuals who have a homozygous expression of antigens? Homozygous expression is directly related to clinically significant antibodies. Stronger reactions are seen with heterozygous cells than with homozygous cells. Weakly reacting antibodies may not agglutinate heterozygous cells. All of the above

Weakly reacting antibodies may not agglutinate heterozygous cells.

10. Solid - phase antibody screening is based on : a . Adherence . b . Agglutination . c . Hemolysis . d . Precipitation .

a . Adherence .

4. Which of the following is a clinically significant antibody whose detection has been reported in some instances to be dependent on anticomplement activ ity in polyspecific AHG ? a . Anti - Jka b . Anti - Lea c . Anti - P₁ d . Anti - H

a . Anti - Jka

A description of the antiglobulin test is : a . IgG and C3d are required for RBC sensitization . b . Human globulin is completely eluted from RBCs during saline washings . c . Human globulin is injected into an animal . d . AHG reacts with human globulin molecules bound to RBCs .

d . AHG reacts with human globulin molecules bound to RBCs .

13. Which of the following is the most common antibody seen in the blood bank after ABO and Rh antibodies ? a . Anti - Fya b . Anti - k c . Anti - Jsa d . Anti - K

d . Anti - K

14. Which uncontrollable factor can affect AHG testing ? a . Temperature b . Antibody affinity c . Gravitational force in the centrifuge d . Incubation time

d . Incubation time

A positive autocontrol in antibody detection procedures is usually indicative of: inadequate washing. positive DAT. positive IAT. none of the above.

positive DAT.

Cells that have antibody attached to them but are still separated from one another are: agglutinated. sensitized. phagocytized. hemolyzed.

sensitized

The M and N antigens exhibit dosage. Therefore, if a person inherits the homozygous genotype MM, their red blood cells will react _______ with anti-M than/as those of a person with a heterozygous genotype of MN. stronger weaker the same none of the above

stronger

When performing the elution procedure, the solution containing the recovered antibody is called: neutralized serum. the buffer. the eluate. absorbed serum.

the eluate.

7 What is a possible consequence of incubating tubes too long with LISS when performing the IAT ? Increased sensitivity Hemolysis Elution of antibody from red blood cells All of the above

Elution of antibody from red blood cells

12 What effect does a low pH have on a saline AHG test ? Enhances antibody elution Enhances the antigen - antibody complex Increases hydrogen bonding Increases bacterial contamination

Enhances antibody elution

Anti-M was detected in a 27-year-old man before surgery. Units negative for M antigen were not available; however, the units were approved for transfusion when major crossmatch using M+N+ donor cells and patient serum resulted in: IS = 1+, 37 = 1+, AHG = 0 IS = 1+, 37 = 0, AHG = 0 IS = 3+, 37 = 2+, AHG = 1+ IS = 2+, 37 = 1+, AHG = 0

IS = 1+, 37 = 0, AHG = 0

The Kell gene is located on the long arm of which chromosome? 5 7 9 11

7

What percentage of the white population inherits the Le gene? 50% 90% 10% 25%

90%

At what phase of the antihuman globulin test will anti-Kell be detected? IS 37°C AHG All of the above

AHG

In order for an individual to express Leb antigen on their red blood cells, they must have inherited which gene? Le Se H All of the above

All of the above

6 How many IgG molecules must be present on the red blood cell for a positive IAT to occur ? A 10 B 100 C 50 D 500

B 100

5 At what temperature is the incubation phase of the AHG test ? A 22 ° C B 37 ° C C 4 ° C D 56 ° C

B 37 ° C

4 Which of the following is consistent with hemolytic disease of the newborn ( HDN ) ? A Recipient antibody coating donor red blood cells B Maternal antibody coating fetal red blood cells C Fetal antibody coating maternal red blood cells D Autoantibody coating individual's own red blood cells

B Maternal antibody coating fetal red blood cells

2 The antihuman globulin ( AHG ) test was discovered in 1945 by whom ? A Landsteiner B Mollison C Coombs D Sanger

C Coombs

When should multiple antibodies be suspected in a positive antibody screen? The auto-control was positive. Cells react at different phases and strengths. Only the AHG phase is reactive. None of the above

Cells react at different phases and strengths.

A patient was phenotyped for the presence of Lewis antigens (Lea and Leb). A 3+ reaction was observed when patient cells were incubated with anti-Lea. No reaction was observed with anti-Leb. Based on these results, the patient's phenotype is _____________ and the patient is a ____________ of ABH substances. Le(a+b-)/secretor Le(a-b+)/secretor Le(a+b-)/nonsecretor Le(a-b+)/nonsecretor

Le(a+b-)/nonsecretor

Why are Lewis antibodies not generally implicated in hemolytic disease of the newborn? Lewis antigens are well developed at birth. Lewis antibodies are IgM and cannot cross the placenta. Lewis antigens can readily dissociate from the red blood cell upon transfusion of Lewis-positive cells. Lewis antibodies do not bind complement

Lewis antibodies are IgM and cannot cross the placenta.

What MN phenotype is found in highest frequency in the white population? M+N+ M+N- M-N- M-N+

M+N+

Persons who are negative for Duffy antigens are less likely to contract which of the following diseases? Chicken pox Influenza Malaria Polio

Malaria

Why are antibodies to high-frequency antigens, such as cellano (k), rarely seen in patient samples? Most persons are not antigenically stimulated to produce the antibody, because their red blood cells are negative for the antigen. Most persons are not antigenically stimulated to produce the antibody, because their red blood cells are positive for the antigen. Anti-k has low avidity. Most reagent cells are heterozygous for cellano

Most persons are not antigenically stimulated to produce the antibody, because their red blood cells are positive for the antigen.

Which cells are employed to remove autoantibody from patient serum without removing any alloantibody from serum? Coombs' control red blood cells Screening red blood cells Patient red blood cells Panel red blood cells

Patient red blood cells

9. Which of the following genotypes would explain RBCs typed as group A Le ( a + b- ) ? a . A / O Lele HH Sese b . A / A Lele HH sese c . A / O LeLe hh SeSe d . A / A LeLe hh sese

b . A / A Lele HH sese

18. Antibody detection cells will not routinely detect which antibody specificity ? a . Anti - M b . Anti - Kpa c . Anti - Fya d . Anti - Lub

b . Anti - Kpa

16. Which antibody does not fit with the others with respect to optimum phase of reactivity ? a . Anti - S b . Anti - P1 c . Anti - Fya d . Anti - Jkb

b . Anti - P1

15. Which would be the most efficient method for a laboratory staffed by medical laboratory technicians ? a . LISS b . Polybrene c . Solid - phase or gel d . Enzyme linked

b . Polybrene

What is the ISBT designation for the Kell system? 001 009 006 100

006

Anti-Lua reacts at what temperature? Room temperature 37°C AHG All of the above

Room temperature

Lutheran antibodies are rarely associated with causing hemolytic disease of the newborn (HDN) for which of the following reasons? Lutheran antigens are poorly developed at birth. Maternal Lutheran antibodies are absorbed onto glycoproteins on the placenta, decreasing the likelihood of HDN. Lutheran antibodies are generally IgM class and normally do not cross the placenta. All of the above

All of the above

What is the purpose of Coombs' control cells? To ensure that AHG tests with negative results are not false-negatives To ensure that washing removed all unbound antibody To ensure that AHG was not omitted or inactivated All of the above

All of the above

When might you suspect multiple antibodies in a patient's serum? Pattern of reactivity not fitting a single antibody Variation in phase of reactivity Variation in antibody reactivity strength All of the above

All of the above

Where are Lewis antigens found? Plasma Saliva Milk All of the above

All of the above

Why is an enzyme treatment used in antibody identification? Enzymes aid in the dissociation of antibody from antigen in a positive DAT. Enzymes aid in the separation and identification of multiple antibodies. Enzymes aid in the absorption of autoantibody from patient serum. Enzymes aid in the separation and identification of multiple antibodies and the absorption of autoantibody from patient serum.

Enzymes aid in the separation and identification of multiple antibodies and the absorption of autoantibody from patient serum.

14 " Complete " agglutinins that agglutinate red blood cells in saline are of which immunoglobulin class ? IgG IgM IgA IgE

IgM

Lewis antibodies are of what immunoglobulin class? IgM IgG IgA IgE

IgM

At which phase are Lewis antibodies usually detected? Immediate spin 37°C Coombs All of the above

Immediate spin

Why is it important to match the lot number on the panel sheet with the lot number on the panel cells? The ABO group will change from lot to lot. Pattern of reactions will change from lot to lot. It is a requirement of the FDA. All of the above

Pattern of reactions will change from lot to lot.

What is the most common use of adsorption? Removal of plasma protein from patient serum Removal of alloantibody from patient serum Removal of autoantibody from patient serum Removal of drug-induced antibody from patient serum

Removal of autoantibody from patient serum

What is the purpose of saline washing in the antibody screen procedure? Removal of bound IgG that would otherwise neutralize the AHG reagent Removal of unbound IgG that would neutralize the AHG reagent Stripping of the red blood cell membrane for alloantibody binding Removal of unbound IgM that would neutralize AHG reagent

Removal of unbound IgG that would neutralize the AHG reagent

9 What is the action of PEG ? Reduces ionic strength to allow for faster antibody uptake Its macromolecules allow for closer contact of antibody - coated RBCs Increases the serum - to - cell ratio Removes water molecules , thereby concentrating antibody

Removes water molecules , thereby concentrating antibody

15 What do " check cells " contain ? A + red blood cell coated with anti - D Rh ( D ) + red blood cells coated with anti - D Rh ( D ) - red blood cells coated with anti - D B + red blood cells coated with anti - D

Rh ( D ) + red blood cells coated with anti - D

During an antibody ID, there was 1+ reaction at AHG with donor cells with the antigen profile Fya(+), Fyb(-). All other donor cells on the panel were negative, including those that were Fya(+), Fyb(+). Given these results, what might be the conclusion? Single antibody (showing dosage) Probably an antibody not represented on the antigen profile An antibody to a high-frequency antigen IgM antibody

Single antibody (showing dosage)

Why are screening cells group O? To prevent interference with anti-A and anti-B in patient serum To prevent interference with A and B antigens on patient cells Because group O cells are easier to acquire in random populations Because group O cells contain antigens to clinically significant antibodies

To prevent interference with anti-A and anti-B in patient serum

10 What is the purpose of washing cells in the AHG test ? To dilute serum To remove all unbound protein To remove all bound protein To exclude a low - affinity antibody

To remove all unbound protein

3. Monoclonal anti - C3d is : a . Derived from one clone of plasma cells . b . Derived from multiple clones of plasma cells . c . Derived from immunization of rabbits d . Reactive with C3b and C3d .

a . Derived from one clone of plasma cells .

5. Transformation to Leb phenotype after birth may be as follows : a . Le ( a - b- ) to Le ( a + b- ) to Le ( a + b + ) to Le ( a - b + ) b . Le ( a + b- ) to Le ( a - b- ) to Le ( a - b + ) to Le ( a + b + ) c . Le ( a - b + ) to Le ( a + b- ) to Le ( a + b + ) to Le ( a - b- ) d . Le ( a + b + ) to Le ( a + b- ) to Le ( a - b- ) to Le ( a - b + )

a . Le ( a - b- ) to Le ( a + b- ) to Le ( a + b + ) to Le ( a - b + )

13. Which of the following IAT methods requires the use of check cells ? a . Manual tube method with albumin b . Gel c . Automated solid - phase analyzer d . Enzyme - linked

a . Manual tube method with albumin

7. A type 1 chain has : a . The terminal galactose in a 1-3 linkage to subterminal N - acetylglucosamine b . The terminal galactose in a 1-4 linkage to subterminal N - acetylglucosamine c . The terminal galactose in a 1-3 linkage to subterminal N - acetylgalactosamine d . The terminal galactose in a 1-4 linkage to subterminal N - acetylgalactosamine

a . The terminal galactose in a 1-3 linkage to subterminal N - acetylglucosamine

3. The Le gene codes for a specific glycosyltransferase that transfers a fucose to the N - acetylglucosamine on : a . Type 1 precursor chain b . Type 2 precursor chain c . Types 1 and 2 precursor chains d . Either type 1 or type 2 in any one individual but not both

a . Type 1 precursor chain

Lewis cell-bound antigens absorbed from plasma onto the red blood cell membranes are: glycoproteins. glycolipids. sphingolipids. ceramides

glycolipids.

8. False - positive DAT results are most often associated with : a . Use of refrigerated , clotted blood samples in which complement components coat RBCs in vitro . b . A recipient of a recent transfusion manifesting an immune response to recently transfused RBCs . c . Presence of antispecies antibodies from adminis tration of immune globulin ( IVIG ) . d . A positive autocontrol caused by polyagglutination .

a . Use of refrigerated , clotted blood samples in which complement components coat RBCs in vitro .

11. Which of the following best describes MN antigens and antibodies ? a . Well developed at birth , susceptible to enzymes , generally saline reactive b . Not well developed at birth , susceptible to enzymes , generally saline reactive c . Well developed at birth , not susceptible to enzymes , generally saline reactive d . Well developed at birth , susceptible to enzymes , gen erally antiglobulin reactive

a . Well developed at birth , susceptible to enzymes , generally saline reactive

The process of removing antibody from serum by combining a serum sample with appropriate red blood cells under optimal conditions is called: elution. absorption. enzyme treatment. sensitization.

absorption

11 Polyspecific AHG contains : anti - IgG anti C3b - C3d . anti - IgG and anti- C3d . anti - IgG and anti IgM .

anti - IgG and anti- C3d .

9. Polyethylene glycol ( PEG ) enhances antigen antibody reactions by : a . Decreasing zeta potential . b . Concentrating antibody by removing water . c . Increasing antibody affinity for antigen . d . Increasing antibody specificity for antigen .

b . Concentrating antibody by removing water .

2. Which of the following characteristics best describes Lewis antibodies ? a . IgM , naturally occurring , cause HDFN b . IgM , naturally occurring , do not cause HDFN c . IgG , in vitro hemolysis , cause hemolytic transfusion reactions d . IgG , in vitro hemolysis , do not cause hemolytic trans fusion reactions

b . IgM , naturally occurring , do not cause HDFN

6. RBCs must be washed in saline at least three times before the addition of AHG reagent to : a . Wash away any hemolyzed cells . b . Remove traces of free serum globulins . c . Neutralize any excess AHG reagent . d . Increase the antibody binding to antigen .

b . Remove traces of free serum globulins .

5. After the addition of IgG - coated RBCs ( check cells ) to a negative AHG reaction during an antibody screen , a negative result is observed Which of the following is a correct interpretation based on these findings ? a . The antibody screen is negative . b . The antibody screen cannot be interpreted c . The saline washings were adequate . d . AHG reagent was added .

b . The antibody screen cannot be interpreted

12. Which autoantibody specificity is found in patients with paroxysmal cold hemoglobinuria ? a . Anti - I b . Anti - i c . Anti - P d . Anti - Pl

c . Anti - P

2. Polyspecific AHG reagent contains : a . Anti - IgG and anti - IgA . b . Anti - IgG and anti - IgM . c . Anti IgG and anti - C3d . d . Anti - IgA and Anti - C3d .

c . Anti IgG and anti - C3d .

15. The null K0 , RBC can be artificially prepared by which of the following treatments ? a . Ficin and DTT b . Ficin and glycine - acid EDTA c . DTT and glycine - acid EDTA d . Glycine - acid EDTA and sialidase

c . DTT and glycine - acid EDTA

14. Which blood group system is associated with resistance to P. vivax malaria ? a . P b . Kell c . Duffy d . Kidd

c . Duffy

17. Which of the following Duffy phenotypes is prevalent in blacks but virtually nonexistent in whites ? a . Fy ( a + b + ) b . Fy ( a - b + ) c . Fy ( a - b- ) d . Fy ( a + b- )

c . Fy ( a - b- )

10. Anti - LebH will not react or will react more weakly with which of the following RBCs ? a . Group O Le ( b + ) b . Group A2 , Le ( b + ) c . Group A1 , Le ( b + ) d . None of the above

c . Group A1 , Le ( b + )

4. What substances would be found in the saliva of a group B secretor who also has Lele genes ? a . H , Lea b . H , B , Lea c . H , B , Lea , Leb d . H , B , Leb

c . H , B , Lea , Leb

11. A positive DAT may be found in which of the following situations ? a . A weak D - positive patient b . A patient with anti - M c . HDFN d . An incompatible crossmatch

c . HDFN

19. Antibodies to antigens in which of the following blood groups are known for showing dosage ? a . I b . P c . Kidd d . Lutheran

c . Kidd

12. What do Coombs ' check cells consist of ? a . Type A - positive cells coated with anti - IgG . b . Type A - negative cells coated with anti - IgG c . Type O - positive cells coated with anti - D d . Type B - negative cells coated with anti - D

c . Type O - positive cells coated with anti - D

Most blood group alleles are: X-linked dominant. X-linked recessive. codominant. none of the above

codominant

16. A 27 - year - old group O mother has just given birth to a group A baby . Since the mother has IgG anti - A , anti - B and anti - A , B in her plasma , which of the following methods and tests would be most effective at detecting the anti - A on the baby's RBCs ? a . DAT using common tube technique b . DAT using gel c . IAT using common tube technique d . IAT using gel

d . IAT using gel

1. The following phenotypes are written incorrectly except for : a . Jk + b . Jka + c . Jkª ( + ) d . Jk ( a + )

d . Jk ( a + )

6. In what way do the Lewis antigens change during pregnancy ? a . Leª antigen increases only b . Leb antigen increases only c . Lea and Leb both increase d . Lea and Leb both decrease

d . Lea and Leb both decrease

7. An in vivo phenomenon associated with a positive DAT is : a . Passive anti - D detected in the maternal sample . b . Positive antibody screen tested by LISS . c . Identification of alloantibody specificity using a panel of reagent RBCs . d . Maternal antibody coating fetal RBCs .

d . Maternal antibody coating fetal RBCs .

8. Which of the following best describes Lewis antigens ? a . The antigens are integral membrane glycolipids b . Lea and Leb are antithetical antigens c . The Le ( a + b- ) phenotype is found in secretors d . None of the above

d . None of the above