Rh, Duffy, Kidd, Kell Flashcards
(142 cards)
1
Q
hWhat two associated proteins are involved in the production of Kell antigens?
a.Kell & Kx
b. Kx & Cellano
c.KEL1 & KEL2
d. Kell & Rh
A
Correct:
a. Kell & Kx
2
Q
Js(a) in a low frequency in what population of people?
a. Native American
b. Asian
c. White
d. Black
A
Correct: c. White
3
Q
The second most immunogenic antibody?
a. Anti-D
b. Anti-k
c. Anti-K
d. Anti-JK(a)
A
Correct: c. Anti-K
4
Q
What Kell phenotype can be artificially made and aids in identifying High Frequency Antigens
a. K0
b. Mcleod
c. Kx
d. Mcleod with CGD
A
Correct: a. K0
5
Q
Which Kell blood system protein is a multipass protein?
a. Kx
b. Km
c. K0
d. Kel
A
Correct: a. Kx
6
Q
Splenomegaly associated with:
a. Mcleod
b. Anti-Km
c. Anti-K
d. Anti-Kx
A
Correct: a. Mcleod
7
Q
A patient with Mclead phenotype and no CGD would require what type of transfusion protocol?
a. Ku Negative Cells
b. Kx & Km Negative Cells
c. Km Negative Cells
d. K Negative Cells
A
Correct: b. Kx & Km Negative Cells
8
Q
A normal Kell phenotype would react ____ to Kell antigens and _____ to KX antigens
a. Strong/Strong
b. Strong/Weak
c. NR/Strong
d. Weak/NR
A
b. Strong/Weak
9
Q
What multipass protein is located on the DARC?
a. Rh
b. Kidd
c. Duffy
d. Kell
A
c. Duffy
10
Q
In the Japanese population the most frequent Duffy antigen is:
a. FY(b)
b. FY4
c. FY3
d. FY1
A
d. FY1 (Fya+)
11
Q
How many co-dominate alleles are involved in the Duffy blood group system?
a. 6
b. 4
c. 2
d. 3
A
b. 4
12
Q
Antibody showing dosage presenting with Big K.
a. Anti-Fy4
b. Anti-Fy3
c. Anti-Fy(x)
d. Anti-Fy(a)
A
d. Anti-Fy (a)
13
Q
What is the most common genotype of African descent when the phenotype is Fy(a+b-)
a. FY/FY
b. FY/Fy(b)
c. Fy(a)/Fy(a)
d. Fy(a)/FY
A
c. Fy(a)/Fy(a)
14
Q
Antibody that is nonreactive with Fy(a+b+) and does not cause transfusion reactions.
a. Anti-FY4
b. Anti-FY3
c. Anti-Fy(a)
d. Anti-Fy(x)
A
15
Q
Fy(x) will adsorp using the eluate of what Antibody
a. Anti-FY3
b. Anti-Fy(x)
c. Anti-Fy(b)
d. Anti-Fy(a)
A
c. Anti-Fy(b)
16
Q
The FY5 antigen is not present on:
a. Rh Null cells
b. Fy(a-b-) cells
c. FyFy Cells
d. Fy6 Cells
A
a. Rh Null cells
17
Q
Which amino acid does Jk(a) end with?
a. Leucine
b. Aspartic Acid
c. Glycine
d. Asparagine
A
c. Glycine
18
Q
Which amino acid does Jk(a) end with?
a. Leucine
b. Aspartic Acid
c. Glycine
d. Asparagine
A
b. Aspartic Acid
19
Q
What Kidd silent allele is associated with those of Polynesian descent?
a. In(JK)
b. JK3
c. JK
d. Jk(a)
A
c. JK
20
Q
JK3 antigen exists if the patient is:
a. In(JK+)
b. JK+
c. JK(a-)
d. JK(a+), Jk(b+), or both
A
d. JK(a+), Jk(b+), or both
21
Q
What antibodies are enhanced by enzymes and likely to have quickly falling titers?
a. Kell
b. Kidd
c. Rh
d. Duffy
A
b. Kidd
22
Q
Antibody detection cells will not routinely detect which antibody specificity?
a. anti-M
b. anti- Kpa
c. anti-Fya
d. anti-Lub
A
b. anti- Kpa
23
Q
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
A
c. DTT and glycine-acid EDTA
24
Q
Which antigen is destroyed by enzymes?
a. P1
b. Jsa
c. Fya
d. Jka
A
c. Fya
25
True or False, Ficin and Papain enhances RH antibodies.
True.
26
Which of the following Rh antigens is the most common in both Caucasian and African American populations?
a. D
b. C
c. c
d. e
Correct: e
The e antigen is a high frequency antigen and is present in about 98& of the population, whether Caucasian or African American.
27
Which of the following Rh antigen is least common in people of African ethnicity and people of European ethnicity?
A. D
B. C
C. E
D. c
E. e
C. E
28
What is the most common Rh haplotype in people of European ethnicity?
A. R1
B. R2
C. RZ
D. r
E. R0
A. R1
29
30 year old African American male with sickle cell disease (HGB SS) presents to a hospital for the first time and requires a blood transfusion. He tells his physicians that he has been transfused heavily in the past but can't recall when or where that occurred. To avoid exposure to blood group antigens to which the patient may have formed alloantibodies, the transfusion medicine specialist chooses to give blood of the Rh phenotype. Statistically speaking, which of the following Rh phenotypes is most likely the best match?
A. R0
B. R1
C. R2
D. RZ
E. r'
A. R0
30
A depression of which of the following antigen systems is associated with chronic granulomatous disease (CGD)?
A. Rh
B. P
C. Kell
D. Duffy
E. Kidd
C. Kell
31
20 year old woman of European ethnicity presents to a mobile blood drive at her college. She fulfills all eligibility criteria and donates a unit of whole blood. The results of her ABO and Rh typings:
Anti A: 0
Anti B: 0
Anti A,B: 0
Anti D: 0
Weak D test: 2+
Weak D control: 0
A1 Cells: 4+
B cells: 4+
Components generated from the donation should be labeled as:
A. ANEG
B. OPOS
C. O weak D
D. APOS
E. ONEG
B. OPOS
32
The same individual describe in Question 6 is involved in an automobile accident 3 months later. Three RBC units are ordered. Which is the safest red cell component to transfuse?
A. ANEG
B. OPOS
C. A weak D
D. APOS
E. ONEG
E. ONEG
33
Another 3 years later, the patient in Question 6 is pregnant. 3 months gestation, her antibody screen is positive. Anti-D is identified. What is the most likely explanation for this finding?
A. Weak D phenotype because of weak D mutation, and now she has allo Anti-D.
B. Partial D genotype, and now she has alloanti-D.
C. Rh negative genotype, and now she has alloanti-D.
D. Weak D phenotype because of a C gene in the trans position to the D gene, and now she has alloanti-D.
E. Rh positive phenotype with an autoanti-D.
B. Partial D genotype, and now she has alloanti-D.
34
Which of the following statements is not true?
A. Kell antigens are located on chromosome 7.
B. Kell antigens are highly imunogenic.
C. Patients with CGD have decreased expression of Kell system antigens.
D. Antibodies to Kell antigens are IgM.
E. All of the above.
D. Antibodies to Kell antigens are IgM.
35
Which of the following statements is not true?
A. The k antigen found on 99% of donor red cells.
B. The Jsa antigen is significantly more prevalent in populations of African ethnicity.
C. Kell antigens are completely destroyed by treatment ficin.
D. The Kell system has two null phenotypes.
E. All of the above.
C. Kell antigens are completely destroyed by treatment ficin.
36
Which of the following statements is true regarding the McLeod phenotype?
A. The red cells have enhanced expression of Kell system antigens and the Kx antigen.
B. Anti-K is detected in the serum.
C. Levels of serum creatine phosphokinase are depressed.
D. It is associated with impaired red cell urea transport.
E. Acanthocytes are seen on the peripheral blood smear.
E. Acanthocytes are seen on the peripheral blood smear.
37
Which of the following characteristics are shared by antibodies with high titer and low avidity?
A. They have strong reactivity with reagent red cells.
B. They are strongly reactive with even high dilutions of patient serum.
C. They may interfere with the detection of clinically significant alloantibodies.
D. They are implicated frequently in hemolytic transfusion reactions (HTRs).
E. They are Ig antibodies best detected with an antiglobulin reagent.
C. They may interfere with the detection of clinically significant alloantibodies.
38
Which of the following antibodies exhibits high titer and low avidity behavior?
A. Anti-Ch
B. Anti-Lub
C. Anti-M
D. Anti-S
E. Anti-Wrb
A. Anti-Ch
39
A patient's serum reacts weakly with 16 of 16 group O panel cells at the antihuman antiglobulin (AHG) phase of testing only. No reaction was noted in the autocontrol. Further testing with ficin treated panel cells demonstrated no reactivity at the AHG phase. Which of the following antibodies is most likely responsible for these results?
A. Anti-Jsa
B. Anti-k
C. Anti-e
D. Anti-Ch
E. Anti-Kpa
D. Anti-Ch
40
Which of the following statements is not true?
A. The Cromer antigens are located on the decay accelerating factor (DAF)/CD55.
B. The Cromer antigens connect to red cells via a glycosylphosphatidylinositol (GPI) linkage.
C. Cromer-negative individuals have a mildly increased sensitivity to complement mediated lysis.
D. Patients with paroxysmal nocturnal hemoglobinuria (PNH) lack Cromer antigens.
E. Cromer antibodies can result in hemolytic disease of he fetus and newborn (HDFN).
E. Cromer antibodies can result in hemolytic disease of he fetus and newborn (HDFN).
41
70 year old male is schedule for right total knee arthroplasty for degenerative joint disease. On pre surgical testing, his antibody screen is found to e positive. Antibody identification shows 1+ panagglutinin at AHG and antibody titer was 512. What is the most likely specificity of the antibody?
A. Anti-e
B. Anti-JMH
C. Anti-Kna
D. Anti-Fyb
E. Autoantibody
B. Anti-JMH
42
Which of the following statements is true?
A. The Colton blood group antigens, Coa and Cob, are located on the red cell membrane protein CHIP-1 (channel forming integral protein-1).
B. The Kidd blood group antigens Jka and Jkb, are located on erythrocyte chemokine receptors.
C. The Cartwright antigens, Yta and Ytbl, are located on DAF/CD55 of erythrocytes.
D. The Cromer antigens are located on erythrocyte acetylcholinesterase (AChE).
E. The Duffy antigens are located on the ureas transport proteins of the kidney.
A. The Colton blood group antigens, Coa and Cob, are located on the red cell membrane protein CHIP-1 (channel forming integral protein-1).
43
What is the titer of anti-K in the serum examined ?
Dilution:
for Anti K
1:1 4+
1:2 3+
1:4 2+
1:8 1+
1:16 m+
1:32 0
1:64 0
1:128 0
A. 8
B. 1:8
C. 16
D. 1:16
E. 1:32
A. 8
44
Which of the following is true concerning the Sda antigen and the antibodies that recognize it?
A. The Sda antigen is expressed on 10% of red cell samples.
B. Sda is located on the C4 component of complement.
C. Anti-Sda is neutralized by human plasma.
D. The presence of anti-Sda is suggested by refractile orange agglutinates on microscopy.
E. Anti-Sda has been associated with HDFN.
D. The presence of anti-Sda is suggested by refractile orange agglutinates on microscopy.
45
Which of the following statements is true of the antigens of the Lutheran blood group system and the antibodies that recognize them?
A. Lua is a high incidence antigen.
B. Anti-Lua causes hemolytic transfusion reactions.
C. The Lu(a-b-) phenotype is common in individuals of African ehthnicity.
D. The Lu(a-b-) phenotype results from an autosomal recessive gene only.
E. Antibodies to Lua produce a mixed field pattern of reactivity with Lua positive cells.
E. Antibodies to Lua produce a mixed field pattern of reactivity with Lua positive cells.
46
30 year old female presents with a lacerated liver following an automobile accident. Four RBC units are ordered. The patient has not history of transfusion but has had five pregnancies. She types as group APOS. Her antibody screen is positive and antibody identification is Anti-D. Rh negative fetal red cells show 3+ at AHG. Rh positive fetal red cells show 3+ at AHG.
Which of the following statements about this antibody and the antigen to which it is directed is true?
A. The antigen is named after its discoverers, Levine and Stetson.
B. The antibody was originally produced by immunizing guinea pigs with red cells from rhesus monkeys.
C. The antigen is destroyed by enzyme treatment.
D. The antibody is capable of fixing complement and causing intravascular hemolysis.
E. The antigen is poorly expressed on fetal red cells.
B. The antibody was originally produced by immunizing guinea pigs with red cells from rhesus monkeys.
47
Which is the most common red cell typing in people of African ethnicity?
A. Lu(a-b-)
B. Jk(a-b-)
C. Fy(a-b-)
D. O h
E. Js(a-b-)
C. Fy(a-b-)
48
Which blood group protein acts as a receptor for the malaria parasite Plasmodium vivax?
A. Duffy
B. MN
C. Kidd
D. Kell
E. Lutheran
A. Duffy
49
Which of the following statements is not true?
A. Kidd antigens are located on the erythroid urea transport protein.
B. Kidd antibodies are IgG.
C. Kidd antibodies are clinically significant.
D. The Kidd null phenotype is rare in Polynesian and Finnish populations.
E. All of the above.
D. The Kidd null phenotype is rare in Polynesian and Finnish populations.
50
Which membrane associated carbohydrate is carried by the human blood group glycophorin molecules?
A. N-acetylglucosamine
B. N-acetylgalactosamine
C. Fucose
D. Galactose
E. Sialic acid
E. Sialic acid
51
A patient with Anti-U requires transfusion. Blood from a donor of which ethnic background is most likely to lack the U blood group antigen?
A. African
B. Asian
C. European
D. Native American
E. All donors are equally likely to lack the U antigen.
A. African
52
Which of the following statements regarding the Diego blood group system is true?
A. The antigens of Diego blood group system are located on the red cell membrane water channel, Aquaporin-1.
B. Dia and its antithetical counterpart, Dib, are high prevalence antigens in most populations studied.
C. Anti-Dia has been implicated in severe cases of HDFN.
D. Antigens of the Diego system are destroyed by proteolytic enzymes (papain, ficin, and trypsin).
E. Dia and Dib are the only antigens in the Diego blood group system.
C. Anti-Dia has been implicated in severe cases of HDFN.
53
Which of the following statements is true regarding the G antigen?
A. The immune response to the antigen appears to be a mixture of anti -C and anti-D.
B. Anti-C,D, and G cannot be distinguished serologically.
C. Obstetric patients who have anti-G are not considered to be suitable candidates for RH Immune Globulin prophylaxis.
D. It is important to distinguish anti-G from anti-C and anti-D in the pretransfusion setting.
E. The immune response to the G antigen is not clinically significant.
A. The immune response to the antigen appears to be a mixture of anti -C and anti-D.
54
30 year old pregnant woman delivers a full term female neonate who is noted to be jaundiced at birth. Laboratory evaluation reveals that the infant has an elevated bilirubin level, is anemic, and has an elevated reticulocyte count. Her direct antiglobulin test (DAT) is strongly reactive, but both she and her mother have negative antibody screens. Which antibody is most likely responsible for these findings?
A. Anti-Cw
B. Anti-Lua
C. Anti-Lea
D. Anti-M
E. Anti-S
A. Anti-Cw
55
The infant described in question 30 requires an exchange transfusion for severe hyperbilirubinemia. Which of the following donors would be most appropriate as a blood group?
A. The infant's mother.
B. The infant's father.
C. The infant's 18 year old brother.
D. Any random blood donor.
E. Blood from a rare donor inventory.
D. Any random blood donor.
56
Which of the following statements is true regarding Rh null and the Rh associated glycoprotein (RhAG)?
A. RhAG is located on chromosome 1 in close approximation to the RH genes.
B. The Rh null phenotype is most commonly results from mutations in the RhAG gene.
C. Cold agglutinins will typically bind to all red cells except those of the rare Rh null phenotype.
D. Despite its name, RhAG is a discrete red cell membrane glycoprotein that does not associate with the Rh complex.
E. Rh null red cells are acanthocytic and are associated with severe hemolytic anemia.
B. The Rh null phenotype is most commonly results from mutations in the RhAG gene.
57
Current phylogenetic analysis suggests that the Rh/RhAG proteins likely have a transporter function for which of the following molecules?
A. Water
B. Anions
C. Urea
D. Ammonia
E. Glycerol
D. Ammonia
58
Which of the following statements regarding the Xg antigen system and its corresponding antibodies is true?
A. Despite its name, the Xga antigen is actually encoded by a gene found on the Y chromosome.
B. The prevalence of the Xga antigen is higher in males than in females.
C. Xga is the only antigen of the Xg blood group system.
D. Xga antibodies are generally IgG but demonstrate a proclivity to agglutinate red cells directly?
E. Anti-Xga is not felt to be clinically significant with respect to hemolysis.
E. Anti-Xga is not felt to be clinically significant with respect to hemolysis.
59
Which of the following statements regarding the Dombrock antigen system and its corresponding antibodies is true?
A. Dombrock system consists of seven antigens including the polymorphic antithetical antigens Doa and Dob.
B. The Doa antigen has a very low prevalence in most population, while the Dob antigen has a high prevalence.
C. Anti-Doa and anti-Dob are usually weakly reactive IgG antibodies that are not considered to be clinically significant.
D. The Dombrock glycoprotein has a structure characteristic of a red cell channel protein.
E. Dombrock antigens are resistant to the disulfide bond reducing agents 2 mercaptoethanol (AET) and diothiothreitol (DTT).
A. Dombrock system consists of seven antigens including the polymorphic antithetical antigens Doa and Dob.
60
Which of the following statements regarding the Colton antigen system and its corresponding antibodies is true?
A. Like many antithetical blood group antigens, Coa is low prevalence while Cob is high prevalence.
B. The Colton antigens are located on the enzyme red cell acetylcholinesterase.
C. Colton antibodies are usually IgG and have been implicated in severe HDFN and hemolytic transfusion reactions.
D. Colton antigens are sensitive to most proteolytic enzymes.
E. Anti-Co3 is only reactive with red cells of the rare Colton-null phenotype.
C. Colton antibodies are usually IgG and have been implicated in severe HDFN and hemolytic transfusion reactions.
61
Which of the following statements is not true?
A. Cartwright antigens are located on complement 4.
B. Cartwright antigens are connected to red cells via a GPI linkage.
C. Cartwright antigens are occasionally responsible for delayed HTRs.
D. Patients with PNH lack Cartwright antigens.
E. Cartwright antibodies are usually IgG.
A. Cartwright antigens are located on complement 4.
62
Which of the following statements regarding the Gerbich antigen system and its corresponding antibodies is true?
A. The Gerbich system antigens are located on glycophorin A and glycophorin B.
B. The Gerbich glycoproteins interact with protein 4.1 and play a role in cytoskeletal membrane integrity.
C. The Gerbich antigens exist in both a membrane associated form and a soluble form in plasma.
D. All Gerbich system antigens are sensitive to proteolytic enzymes.
E. Gerbich antibodies have not been implicated in either hemolytic transfusion reactions or cases of HDFN.
B. The Gerbich glycoproteins interact with protein 4.1 and play a role in cytoskeletal membrane integrity.
63
Which of the following statements regarding the Indian antigen system and its corresponding antibodies is true?
A. The Indian antigens are located on CD44, the primary cell surface receptor for the extracellular matrix protein hyaluronan.
B. Indian antigens have enhanced expression on red cells with the In(Lu) phenotype.
C. Ina and Inb are resistant to treatment with proteolytic enzymes and are also resistant to the disulfide bond reducing agents AET and DTT.
D. Anti-Ina and Anti Inb are generally considered to be clinically significant.
E. Ina is a high prevalence antigen, while the antithetical antigen Inb is a low prevalence antigen.
A. The Indian antigens are located on CD44, the primary cell surface receptor for the extracellular matrix protein hyaluronan.
64
Which of the following statements regarding the Bg antigens and their corresponding antibodies is true?
A. The Bg antigens are the name given to HLA Class II antigens expressed on mature red cells.
B. The Bg antigens are strongly expressed on the red cells of all donors who have the corresponding HLA antigens on their lymphocytes.
C. Bg antibodies are IgG and are always considered to be clinically significant.
D. The Bg antigens are sensitive to treatment with proteolytic enzymes are also sensitive to the disulfide bond reducing agents AET and DTT.
E. Bg antigens can be stripped from red cells with chloroquine.
E. Bg antigens can be stripped from red cells with chloroquine.
65
Which of the following phenotypes will react with an Anti-f?
a. rr
b.R1R1
c. R1R2
d. r'r"
Correct: rr
Note that the antigen is not really “compound”, in that it isn’t formed by the mere presence of c and e on the same red cell, but rather by the action of the Rhce allele that also encodes both c and e. So, it might be better to say that RHce codes for c, e, and f. The f antibody (anti-f) acts much like other Rh antibodies, with evidence of hemolytic disease of the fetus/newborn (HDFN) and possible hemolytic transfusion reactions.
While it might appear on a typical panel/antigram that expressing c and e equals f, the expression is a bit more complex than surface level.
Of the gentoypes listed in the answer selections, only the rr has c and e on the same chromosome.
Here is a depiction of all the possible genotypes and which ones would be f- vs f+
66
A patient is evaluated, and an anti-D found in her serum. The antibody panel is repeated using ficin treated cells. The most likely result is _______?
a. Ficin panel show stronger reactions
b. Ficin panel show weaker reactions
c. No difference in reactions between the two panels.
a. Ficin panel show stronger reactions
It is important to understand that Rh antibodies are ehanced when tested with ficin treated cells (as well as papain).
67
An anti-G would react with all of the cells below except:
a. rr
b. R1r
c. R0r
d. r'r
a. rr
The G antigen is present on most D+ cells and all C+ cells. In the serologic tests, anti-G reacts like anti-C and anti-D and will agglutinate either antigen.
Of the cells listed, only the cell that is rr would be likely to lack the G antigen, and would therefore give a negative reaction with anti-G. The rr combination results in only c and e expression on cells.
R1r has D,C, c, and e on the RBCs
R0R had D, c, and e on the RBCs
r'r has C, c and e on the RBCs
68
Which of the following is a low incidence Rh antigen?
a. Rh29
b. Rh17
c. Rh18
d. Rh37
d. Rh37
Rh37 is called the Evans antigen. It has a frequency of 0.01%. It is produced by the Rh complex D..
Rh29: Also known as Total Rh and is on all red cells except Rhnull
Rh17: Also known as Hr0 expressed by all common Rh haplotypes
Rh18: Also known as Hr, present on all red cells except hrS, Rhnull and RhCE-depleted phenotypes.
69
Individuals that are Goa(+), phenotype as:
a. Category II partial D
b. Category III partial D
c. DBT partial D
c. Category IV partial D
c. Category IV partial D
Goa individuals are category IV partial D. The D antigen is made up of multiple epitopes and those individuals who are missing one or more epitopes are classified as D mosaic. The category number refers to the specific D epitopes that are missing. The Goa antigen replaces the portion of the D that are absent form category IV cells. In fact, if a RBC sample types as Goa (+), we can assume that the individual is a category IV mosaic.
70
What is the most probable genotype (using Weiner nomenclature) of an African American bearting the following reactions: Rh 1,2,-3,4,5
a. RoRo
b. R1r
c. R1Ro
d. Ror
c. R1Ro
There are several steps to solving this problem. First you must know the numeric nomenclature for the RH antigens.
Rh1 = D
Rh2 = C
Rh3 = E
Rh4 = c
Rh5 = e
In this nomenclature, we indicate the negative phenotype by recording a - sign in front of the number. So a D negative individual would be written as RH -1, a D positive individual would be written as Rh1.
In this problem the phenotype is written as: RH 1,2, -3, 4, 5
This means that this indiviual has teh following phenotype: D+C+E-c+e+
Now we need to try to determine the most probable genotype for this person. For an individual who is D+C+E-c+e+, we would typically think that R1r is teh most probably genotype. However, the question tells us that he is African American, so we should be thinking of Ro haplotype is present in about 44% of African Americans so we should look for a genotype that incldues Ro. In this scenaria, the genotype R1Ro would be more common than R1r.
71
A woman types as Rh-positve. She has an anti-c titer of 32 at AHG (this is a clinically significant titer). Her baby has a negative DAT and is not affected by hemolytic disease of the newborn. What is the father's most likely Rh phenotype?
a. rr
b. r''r
c. R1r
d. R2r
c. R1r
72
Refer to the following data:
Rh Genotype: Mother = cde/cde
Father = CDe/cde
These parents would most likely have a child with the genotype:
a. R1R1
b. Ror
c. r'r
d. rr
d. rr
Do a punnet square to determine the possible genotypes. The Rh genes are inherited as a haplotype, rather than as just randomly segragated alleles. since the mom is cde/cde she is an rr, and can pass only the r gene. The father is R1r, which means he can pass on either the R1 or the r gene. Of the possible choices given, only the Rrr (cde/cde) is a possibility, since it is the only choice that offers the correct gene combination.
73
When a C producing Rh gene is in trans-position (the opposite chromosome) to a D producing Rh gene, the following occurs:
a. the D expression is enhanced
b. the D expression is weakened
c. the D antigen is not detectable in routine serologic methods
d. the D expression is not affected
b. the D expression is weakened
When C is in the trans position to D, then the D expression is weakened.
With anti-D reagents being so advanced, we may not see any effects serologically, and the result may be more of a qualitative effect, rather than a cause of a false negative anti-D type.
74
When evaluating anti-D reagent, which cell would be the most helpful in determining that that anti-D can detect weaker expression of D?
a, DcE/DcE
b.Dce/ce
c. ce/ce
d. Dce/Ce
d. Dce/Ce
When evaluating a typing reagent, it is preferred to use cells that have lower dose of the antigen in question. Typically, this means using heterozygous cells to test the efficacy of the reagent in picking up weaker doses of the antigen. In this case, there are two cells that are heterozygous for the D antigen. A cell that is Dce/ce, and a cell that is Dce/Ce. Of these two the Dce/Ce cell would be better because of the C Trans effect.
When the allele carrying the D is trans to the allele carrying C, the D antigen is normal but the steric arrangement of the C antigen in relation to the D antigen interferes with the expression of the D antigen. As a result, you may see weakened expression of the D antigen.
The trans position refers to D and C being on separate chromosomes. For example, c cell that is Dce/Ce may have a trans effect on the D expression, whereas a cell that is DCe/ce will have a normal expression of D. With the potencey of reagents as they are today, you may not actually see a decrease in the serologic reaction of a cell that has D and C in the trans position. However, in this question, since we do know the probable genotype of the 4 cells, we would choose the cell that would give us the weakest expression of the D antigen.
75
A patient sample is tested for type and screen, and gives the following results:
ABO/RH: O Positive
Antibody Screen: Negative
Two units of type specific RBCs are crossmatched through the IAT phase, at which is the policy of the blood bank. One unit is 2+ incompatible at IAT phase and has a negative DAT.
Which Rh antibody is most likely responsible for this type of scenario?
a. anti-c
b. anti-G
c. anti-Cw
d. anti-f
c. anti-Cw
When there is a negative antibody screen and an incompatible crossmatch, we should think of two situations: a donor unit with a positive DAT or a patient with an antibody to a low frequency antigen.
We have ruled out the DAT + donor unit, so we should think of the presence of an antibody directed against a low frequency antigen.
Of the antigens listed, only anti- Cw would be unlikely to react with screen cells. It is common for screen cells to lack Cw antigen. The Cw antigen is presen in about 2% of Caucasians and is very rare in African Americans.
The c antigen in prevalent in 80% of individuals
The G antigen has a prevalence of about 86%
The f antigen is present in about 64% of the population.
Based on the other antigen frequencies, it is likely both crossmatches would be incompatible.
76
A 40 year old group O Negative male, with no history of transfusion has a hemoglobin of 6.0. The physician decides to transfuse 2 units of RBCs, but no Rh negative units are available. Two units of O Positive RBCs are transfused to this patient. The most likely result will be ______ .
a. An immediate hemolytic transfusion reaction
b. A delayed transfusion reaction
c. A positive DAT, but no clinical evidence of transfusion reaction
d. No transfusion reaction, no positive DAT
d. No transfusion reaction, no positive DAT
Rh antibodies are typically IgG in nature and not formed until the secondary immune response.
The patient is D- and is being exposed to D+ cells for the first time. As a result, he may respond by making an IgM anti-D. The primary response is usually of lower titer, and does not cause hemolytic transfusion reactions (HTR).
If the patient would be exposed to D+ RBCs a second time after making an anti-D then the secondary immune response would occur in which higher titers of IgG anti-D would be produced, leading to a delayed hemolytic transfusion reaction and most likely a positive DAT.
77
A first time blood donor is phenotyped for Rh antigens, and the following results are obtained.
Anti-D = 0
Anti-C = 0
Anti-E = 0
anti-c = 0
anti-e = 0
What is the most probably cause for these results (assume that the serology was done correctly and that the QC was acceptable)
a. D--
b. D..
c. rr genotype
d. Rh null
d. Rh null
78
A patient specimen is evaluated, and an anti Rh-29 is identified in the serum. Which of the cells below would test negative with this patient specimen?
a. D--
b. D..
c. rr genotype
d. Rh null
d. Rh null
Rh null individuals do not express common Rh antigens. In routine serologic testing, someone who is Rh null would type negative and without doing the rest of the phenotype may be missed as being Rh null. Many Rh null individuals make an antibody that reacts with all cells except that of other Rh null individuals. This antibody is cells "anti-total-Rh" or anti-Rh29
79
A mother has an anti-Lw(a) which reacts 2+ at AHG phase. It is suspected that her fetus is Lwa+. What is the most likely result in this situation?
a. Baby will suffer from severe Hemolytic Disease of the Newborn (HDFN)
b. Baby will not suffer from severe Hemolytic Disease of the Newborn (HDFN)
b. Baby will not suffer from severe Hemolytic Disease of the Newborn (HDFN)
Anti-Lw has not been reported to cause severe HDN.
80
The Rhnull phenotype can be a result of 2 different mechanisms. Which is the most common?
a. amorph
b. regulator
c. Y-linked recessive gene
d. Inheritance of CIS product antigens
b. regulator
Rh null can arise from two mechanisms
In the less commonly seen condition, the person inherits two amorphic RH genes which results in no production of the common Rh antigens.
In the regulator type Rh null the RHAG gene is mutated. Because the RHAG gene is nonfunctional there is a complete absence of the core RH polypeptides necessary for the production of normal RH antigens.
It is important to understance the two mechanisms of becoming Rh null and has been seen on the SBB exam.
81
If a patient has an anti-hrb (RH31), which of the following RBC units would be compatible?
a. R1R1
b. rr
c. R2R2
d. R1R2
c. R2R2
If a patient has an anti-hrb, he is producing a variant of anti-e so avoid giving the patient e antegen positive blood. Out of the above options, R2R2 is the best because it lacks the e antigen (DcE/DcE) and hrb is not on R2R2.
82
If a patient has a positive antibody screen, a request for a red blood cell (RBC) product transfusion will be delayed due to the extra testing that is now required to identify the antibody and find compatible RBCs. Whic of the following antibodies would be most likely to cause the shortest transfusion delay?
a. anti-K
b. anti-Jka
c. anti-E
d. anti-s
a. anti-K
If a patient has an antibody against a red blood cell antigen, their compatibility with the donor population is decreased. A patient with a so-called "clinically significant" antibody must receive RBCs that antigen type negative for the corresponding antigen. An antibody is considered clinically significant if it can either cause a hemolytic transfusion reaction or hemolytic disease of the fetus and newborn (HDFN). Such antibodies are usually antibodies of the IgG isotype that cause agglutination at 37 C. The lower the frequency of the antigen in the population, the better chance you have of finding compatible RBCs for the patient.
In this case the antigen frequencies (in a primarily U.S. Caucasian donor pool) are K: 9% Jka: 77% E:29% s: 89%
Since the frequency of K is 9% in these donors, a patient with anti-K is compatible with 91% of the population.
83
If a patient has anti-c and anti-S, how many RBC units will the transfusion service need to test in order to find 2 units that are compatible with the patient?
Frequencies:
c = 80%
C = 68%
s = 90%
S = 55%
a. 12
b. 22
c. 32
d. 42
b. 22
When the patient has more than one antibody, multiple the compatibility frequencies of each antigen to calculate the percentage of RBC units compatible.
The frequency of the c antigen is 80% (20% compatible with the patient)
The frequency of the S antigen is 55% (45% compatible with the patient)
Multiply the negative frequencies together: 0.2 x 0.45 = 0.09
of RBC units to test = 2 / 0.09 = 22 units
84
A patient has a positive antibody screen and positive antibody panel. The patient specimen is retested with antibody panel cells that have been treated with the enzyme, ficin. The antibody panel is now negative.
Which of the following antibodies would give you these results?
a. anti-D
b. anti-K
c. anti-Jka
d. anti-Fya
d. anti-Fya
Ficin destroys certain common antigens found on red blood cells, which include: Fya, Fyb, M, N, S, s, Xga. If a patient has an antibody against one of these antigens the test result will be negative after the reagent red cells are treated with the enzyme since there is no longer a target antigen for the antibody.
Keep in mind that the patient still has the antibody. The antibody reactivity is just not detected using ficin treated panel cells.
Enzymes destroy antigens, not antibodies.
85
A technologist wishes to distinguish between an anti-Fy3 and anti-Fy5. Which cells below will give her the best result to help differentiate between the two antibodies?
a. Fy (a-b-) cell
b. Fy (a-b-) Cord Blood Cell
c. Fy (a+b+) Rhnull cell
d. Fy (a-b-) Rhnull cell
c. Fy (a+b+) Rhnull cell
If you use the Fy (a-b-) cell, then both anti-Fy3 and anti-Fy5 would react negative against this cell.
Anti-Fy3 will react with an Rhnull cell that has Fya and/or Fyb antigens
Anti-Fy5 will not react with Rhnull cells of any Fy phenotypes.
86
AWhich of the following techniques/reagents would be LEAST useful in the detection of anti-Jka?
a. Low Ionic Strength Saline (LISS)
b. Proteolytic enzymes
c. Polyethylene glycol (PEG)
d. Saline Room Temperature
d. Saline Room Temperature
anti-Jka is typically and IgG class antibody. IgG class antibodies do not react best at room temperature slaine conditions; reactivity is best seen at the IAT phase.
Proteloytic enzymes enhance Kidd antibodies.
PEG would increase the sensitivity for detecting Kidd antibodies.
87
A D+ patient presented with a positive antibody screen and an antibody that appeared to anti-D. The patient's auto-control was negative. The antibody was denatured by DTT treatment. What is the most probably identity of the antibody?
a. auto-anti-D
b. allo-anti-D
c. anti-LW
d. Anti-G
c. anti-LW
Anti-LW could be mistaken for an alloanti-D when it's weak since D+ cells have stronger expression of the LW antigen.
The fact that the reactivity disappeared when the cells were treated with DTT reinforced the fact that this antibody is really anti-LW; the D antigen is not weakened by DTT treatment (this is true for the anti-D made by Rh negative individuals as well as that made by partial D individuals).
A strong anti-LW may react with all cells, showing a stronger reaction on D+ cells.
88
A patient is shown to be Ena negative. Which choice below is consistent with a phenotype for an Ena negative person?
a. M-N+S-s-
b. M-N+S=s+
c. M-N-S+s-
d. Mg+N+S+s=
c. M-N-S+s-
Ena negative individuals do not produce Glycophorin A. The MN antigen reside on Glycophorin A so the patient would type as M-N-.
89
Which RBC phenotype below would be compatible witha patient who has anti-G?
a. R1rFy(a-b-),M-N+S-s-
b. RoR2Fy(a-b+), M-N-S-s+
c. r'rFya(Fa+b-),M-N+S-s+
d. rr(Fya+b+), M-n-S+s+
d. rr(Fya+b+), M-n-S+s+
Anti-G reacts the same as a non-separable anti-C with anti-D. Therefore, any cells that are D+ and/or C+ will most likely also have the G antigen and react with anti-G.
Of those listed, only the rr cell (dce/dce) will not react witht he patient serum. Other antigens besides D and C will not interact with anti-G.
R1r = DCe/dce = positive for D and C antigens
RoR2 = Dce/DcE = positive for the D antigen
r'r = dCe/dce = positive for the C antigen
90
Which of the following phenotypes will not react with an anti-Ku?
a. Ko
b. K-k+
c. Kp (a-b+)
d. K-k+, Kp(a-b+), Js(a+b+)
a. Ko
The Ku antigen is often referred to as K universal, any individuals that have Kell antigens will also have the Ku antigen.
Anti-Ku is the antibody that is produced by Kell null individuals (Ko) and will react with the Kell antigens listed in the other choices.
91
Why is determination of Rh status crucial for obstetric patients?
a. All Rh negative mothers are possible candidates for Rhogam
b. All Rh positive mothers are possible candidates for Rhogam
c. All Rh negative mothers can form anti-D if she gives birth to an Rh negative infant
d. All Rh positive mothers can form anti-D that will destroy D positive fetal red cells.
a. All Rh negative mothers are possible candidates for Rhogam
92
The Rh gene is located on which chromosome?
a. 9
b. 1
c. 7
d. 11
b. 1
93
Why is it imperative that homozygous cells be employed when ruling out Kidd antibodies?
a. It will reduce the number of false positive results
b. anti-Jka may appear compatible with homozygous cells
c. anti-Jka may appear compatible with heterozygous cells
d. Heterozygous cells are rare and difficult to acquire
c. anti-Jka may appear compatible with heterozygous cells
94
What Kidd antibody will react with all positive cells but not the autocontrol?
a. anti-Jsa
b. anti-Jka
c. anti-Jk3
d. Anti-Jkb
c. anti-Jk3
95
Persons with the McLeod phenotype do not express this marker.
a. Jsb
b. Kpa
c. k
d. Kx
d. Kx
96
DTT will destroy which blood group antigen?
a. Fya
b. Kell
c. P
d. Jkb
b. Kell
97
Chronic granulomatous disease (CGD) is associated with what phenotype?
a. Jk (a-b-)
b. Fy (a-b-)
c. McLeod
d. Ko
c. McLeod
98
This antibody typically causes red cells to exhibit a refractile shiny appearance, and mixed field reactions at AHG, and can be neutralized by most human urine.
a. Sda
b. P1
c. Bga
d. Lua
a. Sda
99
Which of the following is true regarding the Diego antigens?
a. They are not destroyed by enzymes
b. They are destroyed by enzymes
c. Low prevalence among people of South America
d. Antigens are not antithetical
a. They are not destroyed by enzymes
100
How would an R1R1 person translate to Rosenfield terminology in the Rh system?
a. Rh: 1,2,-3-,4,5
b. Rh: -1,2,-3,4,5
c. Rh: 1,-2,3,-4,5
d. Rh: 1,2,3,4,5
a. Rh: 1,2,-3-,4,5
101
Anti-C is found in an O negative patient going to surgery. What type blood should you prepare for transfusion?
a. r'r' type O
b. rr type O
c. R1R1 type O
d. R2R2 type O
b. rr type O
102
What antibody might you suspect in a patient of Polynesian heritage?
a. Anti-Jk3
b. Anti-Fya
c. Anti-K
d. Anti-Lua
a. Anti-Jk3
103
A patient on antithymocyte globulin therapy may produce antibodies that mimic what specificity?
a. Duffy
b. Rh
c. Lutheran
d. P1
c. Lutheran
104
Which of the following Fisher-Race phenotype compares with Roesenfield's Rh: 1,-2,3,4,-5?
a. R2,R2
b. R1R1
c. rr
d. R2r
a. R2,R2
105
A patient has formed anti-KL. What patient population's RBC's might be compatible?
a. Persons with PNH
b. McLeod persons
c. Dantu persons
d. Rh nulls
b. McLeod persons
106
anti-rhi react with what phenotype?
a. R1R2
b. ROr
c. R2R2
d. R2r
a. R1R2
107
Which cells would be devoid of glycophorin B?
a. S and s
b. Mk/Mk
c. S and U
d. N
b. Mk/Mk
108
What is unique about the In(Jk) gene?
a. Resistance to sickling
b. Resistance to lysis in 2M urea
c. Results in decreased P1
d. Susceptible to lysis in 2M urea
b. Resistance to lysis in 2M urea
109
A patient whose red cells type as D+C-E-c-e-Evans+ could form what antibody?
a. Anti-Hro
b. Anti-G
c. Anti-rhi
d. Anti-Rh29
a. Anti-Hro
110
What does rh' represent in the Weiner nomenchlature?
a. e
b. C
c. c
d. E
b. C
111
Which of the following may produce anti-RH29?
a. A person with a mosaic D
b. Rh null person
c. A person who has C trans to D
d. All of the above
b. Rh null person
112
Cellano would have strong expression in all of the following except:
a. K-k+Kp(a+b+)
b. K+k+Kp(a-b+)
c. K-k+Kp(a-b+)
d. K-k+Kp(a+b-)
d. K-k+Kp(a+b-)
113
This antigen is not altered by ficin or papain?
a. Fy3
b. Fya
c. Fyb
d. Fy6
a. Fy3
114
What antibody may be made from Ko individuals?
a. Anti-Ku
b. Anti-Kn(a)
c. Anti-Kn(b)
d. Anti-KL
a. Anti-Ku
115
The cde/cde genotype has the least amount of what antigen
a. f
b. LW
c. c
d. e
b. LW
116
Which of the following represents a null phenotype?
a. INAB
b. Fy5
c. SC1
d. Hy
a. INAB
117
What true concerning Rh null cells?
a. They are negative for Jk3
b. They are negative for Fy5
c. They are negative for S
d. all of the above
b. They are negative for Fy5
118
What Rh antibody is typically described as allanti-e like?
a. anti-hrb
b. anti-G
c. anti-f
d. anti-cx
a. anti-hrb
119
Which Rh antigen is high frequency?
a. Bea
b. Evans
c. hrH
d. HrB
d. HrB
120
Which of the following represents decreasing immunogenicity for major Rh antigens?
a. D>c>E>C>e
b. D>E>C>e>c
c. D>c>e>E>C
d. D>e>c>C>E
a. D>c>E>C>e
121
This Rh antigen is a low incidence antigen associated with partial D phenotype DFR
a. JAL
b. FPTT
c. Crawford
d. MAR
b. FPTT
122
The high frequency antigen Santini (Kell System) is antithetical to:
a. Callais
b. Sutter
c. Matthews
d. Rautenberg
a. Callais
123
A red blood cell identified as rGr would yield postive results with:
a. anti-f, anti-E, anti-G
b. anti-f, anti-G, anti-rhi
c. anti-f, anti-G
d. anti-f, anti-G, anti-Goa
c. anti-f, anti-G
124
BARC is associated with which partial D category?
a. IV
b. III
c. VI
d. I
c. VI
125
A patient with the phenotype K-k+Kp(a+b-) would have a weakened:
a. k antigen
b. Km antigen
c. Kx antigen
d. K:12
a. k antigen
126
A 31 year old female is 20 weeks into her pregnancy when seen by an ER physician for severe cramping. She types as O positive initially, however at AHG phase types as D negative using tube testing. Molecular testing is done which reveals the presence of c and e antigens, absence of DCE, and presence of DHAR and FPTTT. can this patient receive Rh positive blood?
a. Yes, RhD gene is no encoded
b. No, patient carries the RHCEceHAR allele
c. es, patient carries the RHD*01 allele
d. No, patient is Del
b. No, patient carries the RHCEceHAR allele
127
An Xg(a+) woman who marries an Xg(a-) man can bear:
a. Xg(a-) daughters
b. Xg(a+) daughters
c. Xg(a+) sons
d. all of the above
d. all of the above
The woman would be Xga/X and the man would be XY. If you put those genotypes into a punnet square then you can see the possible genotypes of the offspring.
128
Calculate the combined phenotype frequency of c-K-Jk(a-) individuals.
a. 0.02
b. 0.04
c. 0.08
d. 0.10
The correct response is 0.04. You will likely see a question like this in which you are expected to recall the frequencies of antigens from memory. To calculate, you multiply the frequencies of the negative phenotypes. c- is 0.2 (20%), K- is .91 (91%), Jka- is 0.23 (23%) therefore, multiply (0.20)(0.91)(0.23) = 0.42 Round of to 0.4
Also, if not mentioned, assume that the donor population is Caucasian, since the majority of donors are in fact Caucasian. If the problem specifically mentions a racial or ethnic population, then you would need to recall those frequencies. It is far more common to see the problem with No mention of races or ethnicities.
129
A specimen of RBCs give the following reactions with Rh-hr antisera:
anti-D: +
anti-Rhi: +
anti-f: +
The most probably RH genotype for this patient is:
a. R0r
b. R1r
c. R2r
d. R1R1
b. R1r
Anti-Rhi reacts with cells that have C and e on the same chromosome. Anti-f reacts with cells that have c and e on the same chromosome. Therefore, person must be Ce/ce, so R1r is the only correct choice (DCe/dce).
130
Which of the following phenotypes is related to resistance to malaria?
a. Le (a-b-)
b. Jk (a-b-)
c. Fy (a-b-)
d. Rh null
c. Fy (a-b-)
Fya and Fyb genes are receptors for the malaria organisms. RBCs which lack Fya and Fyb antigens are resistant to malaria.
131
Which of the following observations suggest that the patient's blood is the McLeod phenotype?
a. K-, k+
b. K-, k-
c. K-, k+w
d. K+w, k+w
c. K-, k+w
Mcleod phenotype individuals typically type as weak+ for k, Kpa, and Jsb. You don't see K+ reactions in Mcleod.
132
A technologist opens a new vial of anti-C and performs testing on 3 units of RBC and two control specimens. The positive control is an Ror cell, and the negative control is a rr cell. All 3 unit RBCs react positive, but both controls are negative. What should be done?
a. Repeat the testing using a new vial of anti-C
b. Repeat the positive control only
c. Label the unit as C negative, then obtain 3 more units for testing
d. Repeat the testing using different controls
Repeat the testing using different controls. The positive control was not properly selected. The Ror cell would have the Dce antigens, and as such is C-. Although the donor unit samples all were positive, the test is invalid. Select a proper C+ cell, and repeat the testing.
133
Anti-Fy3 can be distinguished from anti-Fy5 based on reactions with which type of RBCs?
a. Fy (a-b-)
b. Rh null
c. Fy (a+b+)
d. Enzyme treated Fy (a-b-)
b. Rh null
Anti-Fy5 will not react Rh null cells, but anti-Fy3 will react with Rh null cells
134
An individual who is Ko will have which of the following antigens on the RBC membrane?
a. Ku
b. Kx
c. Ko
d. K11
b. Kx
An individual who is Ko (or Kell null) will lack all Kell system antigens EXCEPT Kx. These Ko individuals are capable of making antibodies to all Kell system antigens that are lacking. The Ku antigen appears on all cells except for Ko cells. Ko individuals are capable of making an anti-Ku (K Universal). The Kx antigen actually has enhanced reactivity when other Kell system antigens are denatures, or missing. It was originally believed to be a precursor to Kell system antigens, but that theory was dismissed. The Kx antigen now resides in its own blood group system called XK.
135
Select the strongest to weakest expression of Rh given the inherited traits below.
a. R2R2>R1R2>R1R1>D-
b. D->R2R2>R1R2>R1R1
c. D->R1R2>R1R1>R1R2
d. R2R2>D->R1R1>R1R2
b. D->R2R2>R1R2>R1R1
136
Goa is a low frequency antigen in the Rh system found on red cells lacking part of the D mosaic representing which category?
a. category V
b. category IVa
c. category III
d. category IV
b. category IVa (GoDIVA)
The Goa antigen was first described in 1956 as a low-frequency Rh antigen found predominantly in persons of African descent. Goa specificity is limited to category IV of the Tippett and Sanger classification. In 1967, an antibody was identified in the mother of an infant with hemolytic disease of the newborn and was labeled as anti-Gonzales, after the patient's surname.
137
Which of the following treatments is useful when distinguishing between anti-D and anti-Lw?
a. chloroquine
b. cord cells
c. ficin
d. dithiothreitol
d. dithiothreitol
LW antigens require divalent cations (e.g. 2+) for expression and have intramolecular disulfide bonds that are sensitive to dithiothreitol (DTT) treatment.
DTT treatment is helpful to differentiate anti-LW from anti-D, because the D antigen is resistant to DTT while LW antigen is sensitive to DTT.
LW antigens are expressed equally wel on group O D-positive and D-negative cord blood red cell.
Cord cells are not considered a treatmetn and often used in conjunction with DTT results to confirm the presence of either antibody.
Ficin (breaks down proteins) and chloroquine (dissociates bound antibody from RBCs/destroys HLA antigens) do not disrupt disulfide bonds.
138
When 1,000 donors were tested, 75% were positive for C and 25% were negative for C; the gene frequency of C is:
a. 0.75
b. 0.86
c. 0.5
d. 0.25
c. 0.5
First, note the sample size is large (1,000). HW assumes large population.
Consider the Hardy Weinberg equation where P^2 +2PQ+Q^2 = 1.00
P^2 = C+ (homozygous for C) and negative for second allele
2PQ = C+ (heterozygous for both alleles)
Q^2 = Negative for C (Homozygous for second allele)
Therefore Q^2 = 25% or 0.25
Also consider the equation P+Q = 1.00
Where P = one gene
Q = allelic gene
If Q^2 = 0.25 then the square root of Q = 0.5
P+Q = 1.00
P = 1.00-Q or 1.00 therefore P=0.5
Frequency of C gene is 0.5
139
Of the following Rh gene complexes, which one gives rise to a red blood cell antigen that gives a positive reaction with anti-Rh^i sera?
a. RHCe
b. RHcE
c. RHce
d.RHCE
a. RHCe
The SBB exam incorporates questions that ask about gene complexes rather than antigens, especially for the antibodies that react only with certain genetic features, such as anti-Rhi or anti-f.
First, we need to know that anti-Rhi reacts only with cells that have C and e on the SAME chromosome.
Remember that there are three genes that work together to create a persons RH genotype. The RHAG, RHD, and RHCE genes. I left the RHD genes out to make it more readable for you, but on the SBB exam you might see the genotype, rather than the gene complex, so it would be RHDRHCe.
RHCe has both C and e on the same chromosome (gene complex R1 or r' depending on the D type)
RhcE is R2 or r' (depending on the D type)
RHce is Ro or r (depending on the D type)
RHCE is RZ or r^y (depending on the D type)
140
Persons who inherit the In(Jk) gene will exhibit:
a. Jk(a-b+) red blood cells that can elute anti-JK3
b. Jk(a+b-) red blood cells that can elute anti-JK^a
c. Jk(a+b-) red blood cells that can absorb anti-JK3
d. Jk(a-b-) red blood cells that can absorb anti-JK^a
d. Jk(a-b-) red blood cells that can absorb anti-JK^a
The In(JK) gene is an inhibitor gene, and it prevents normal expression of Jk antigens on the RBC membrane. Therefore a person can be genetically Jk+, but not have fully expressed Jk^a antigen in detectable amounts on the RBC membrane. However, these cells can typically absorb anti-Jk^a.
While not all people who have the In(Jk) gene will be Jk+, and this answer will not be true in all cases, it is still the only correct response. Inheriting the In(Jk) gene results in phenotypically Jk(a--b-) RBCs, so you can rule out the other three choices.
This is a typically SBB exam question, it may not be true 100% of the time, but all the other options are not viable.
141
How were Au^a and Au^b initially linked to the Lutheran system?
a. enhanced by enzymes (trypsin)
b. Well-expressed on cord cells
c. Suppression by In(Lu) gene
d. Antigens are carbohydrate chains on the RBC membrane.
c. Suppression by In(Lu) gene
You may not remember this from the reading, and may think this is too esoteric to include on the exam. But again, it is an example of an SBB exam question where you are called upon to use your reasoning skills. As you review the choices, three of them do not even apply to the Lutheran blood group system.
Lutheran antigens have been detected on fetal cells, but they are poorly developed at birth, so we ca rule out that answer. In addition, Lutheran antibodies are not enhanced by enzymes they are unaffected. so we can rule that one out as well.
Lutheran antigens are glycoproteins, not carbohydrates so we can also rule out that choice. Auberger antigens are not present on RBCcs that are Lu(a-b-).
From the perspective of the SBB authors, any blood bank topic is fair game. I included this question here because you will see a question or two on the exam with something that you have never thought to study (like the Auberger antigens).
142
A patient with anti-K and anti-Jka needs to units of RBCs for surgery. How many group specific units would need to be screened to find two that are compatible.
a. 6
b. 10
c. 20
d. 36
b. 10
Note that the question states GROUP SPECIFIC. This means that we are only screening ABO matched units, so we can eliminate ABO frequencies from our calculations.
If the question asks about random donors, then you need to factor in the ABO frequencies into your equation.
The equation is: # compatible units/100 = # desires/X (Where X is the number of units to screen)
We want 2 units of K-, JKa- RBCs. The percentage of K- is 91% and jka is 24%.
So we first divide those percentages by 100 (convert to the decimal).
Now we multiply those two values together (0.91)(0.24) = 0.2184
So our question is now 0.2184 = 2/X
Now divide both sides by 0.2184 to get X by itself, which gives you the equation
X= 2/0.2184 = 9.157
Always round to the next highest whole number, since you can't screen a fraction of a unit.
So the final answer is 10 units.
You will need to memorize the frequencies for the more common antigens: D, C, E, c, e, K, k, Fya, Fyb, Jka, Jkb, S, s, M, N, Lea, Leb.
The math questions will not typically include Lea, Leb, M, N, in the equations for finding compatible units since these antibodies are usually NOT clinically significant. However, you should still know the frequencies of the antigens as it will help you with antibody ID problems on the exam.
