Assessment BB Flashcards
What type of serological testing does the blood bank technologist perform when determining the blood group of a patient?
a. Genotyping
b. Phenotyping
c. Both genotyping and phenotyping
d. Polymerase chain reaction
b. Phenotyping
Phenotyping, or the physical expression of a genotype, is the type of testing routinely performed in the blood bank. An individual, for example, may have the AO genotype but phenotypes as group A.
Which genotype(s) will give rise to the Bombay phenotype?
a. HH only
b. HH and Hh
c. Hh and hh
d. hh only
d. hh only
The Bombay phenotype will be expressed only when no H substance is present. The Oh type is expressed by the genotype hh. Bombays produce naturally occurring anti-H, and their serum agglutinates group O red cells in addition to red cells from groups A, B, and AB persons.
Which of the following describes the expression of most blood group antigens?
a. Dominant
b. Recessive
c. Codominant
d. Corecessive
c. Codominant
The inheritance of most blood group genes is codominant, meaning that no gene or allele is dominant over another. For example, a person who is group AB expresses both the A and B antigen on his or her red cells.
What blood type is not possible for an offspring of an AO and BO mating?
a. AB
b. A or B
c. O
d. All are possible
d. All are possible
A mating between AO and BO persons can result in an offspring with a blood type of A, B, AB, or O.
A patient’s serum is incompatible with O cells. The patient RBCs give a negative reaction to anti-H lectin. What is the most likely cause of these results?
a. The patient may be a subgroup of A
b. The patient may have an immunodeficiency
c. The patient may be a Bombay
d. The patient may have developed alloantibodies
c. The patient may be a Bombay
What antibodies are formed by a Bombay individual?
a. Anti-A and anti-B
b. Anti-H
c. Anti-AB
d. Anti-A, anti-B and anti-H
d. Anti-A, anti-B and anti-H
A Bombay individual does not express A, B, or H antigens; therefore anti-A, B, and H are formed. Because a Bombay individual has three antibodies, the only compatible blood must be from another Bombay donor.
Acquired B antigens have been found in:
a. Bombay individuals
b. Group O persons
c. All blood groups
d. Group A persons
d. Group A persons
The acquired B phenomenon is only seen in group A persons.
Which typing results are most likely to occur when a patient has an acquired B antigen?
a. Anti-A 4+, anti-B-3+, A1 cells neg, B cells neg
b. Anti-A 3+, anti-B neg, A1 cells neg, B cells neg
c. Anti-A 4+, anti-B 1+, A1 cells neg, B cells 4+
d. Anti-A 4+, anti-B 4+, A1 cells 2+, B cells neg
c. Anti-A 4+, anti-B 1+, A1 cells neg, B cells 4+
In forward typing, a 1+ reaction with anti-B is suspicious because of the weak reaction and the normal reverse grouping that appears to be group A. This may be indicative of an acquired antigen. In the case of an acquired B, the reverse grouping is the same for a group A person.
Which blood group has the LEAST amount of H antigen?
a. A1B
b. A2
c. B
d. A1
e. O
a. A1B
The A1B blood group has the least amount of H antigen. This is due to both A and B epitopes present on red cells compromising the availability of H epitopes. A1B cells will yield weak reactions with anti-H lectin.
What should be done if all forward and reverse ABO results are negative?
a. Perform additional testing such as typing with anti-A1 lectin and anti-A,B
b. Incubate at 22°C or 4°C to enhance weak expression
c. Repeat the test with new reagents
d. Run an antibody identification panel
b. Incubate at 22°C or 4°C to enhance weak expression
All negative results may be due to weakened antigens or antibodies. Room temperature or lower incubation temperature may enhance expression of weakened antigens or antibodies.
N-acetyl-D-galactosamine is the immunodominant carbohydrate that reacts with:
Arachis hypogaea
Salvia sclarea
Dolichos biflorus
Ulex europaeus
Dolichos biflorus
The immunodominant sugar N-acetyl-galactosamine confers A antigen specificity when present at the terminus of the type 2 precursor chain on the RBC membrane. Therefore, its presence would cause RBCs to react with anti-A1 lectin, Dolichos biflorus.
A stem cell transplant patient was retyped when she was transferred from another hospital. What is the most likely cause of the following results?
Patient cells: Anti-A, neg Anti-B, 4+
Patient serum: A1 cells, neg B cells, neg
a. Viral infection
b. Alloantibodies
c. Immunodeficiency
d. Autoimmune hemolytic anemia
c. Immunodeficiency
WEAK OR MISSING ANTIBODIES
A transplant patient is probably taking immunosuppressive medication to increase graft survival. This can contribute to the loss of normal blood group antibodies as well as other types of antibodies.
A complete Rh typing for antigens C, c, D, E, and e revealed negative results for C, D, and E. How is the individual designated?
a. Rh positive
b. Rh negative
c. Positive for c and e
d. Impossible to determine
b. Rh negative
Rh positive refers to the presence of D antigen; Rh negative refers to the absence of the D antigen. These designations are for D antigen only and do not involve other Rh antigens.
A patient tests positive for weak D but also appears to have anti-D in his serum. What may be the problem?
a. Mixup of samples or testing error
b. Most weak D individuals make anti-D
c. The problem could be due to a disease state
d. A D mosaic may make antibodies to missing antigen parts
d. A D mosaic may make antibodies to missing antigen parts
The D antigen is comprised of different parts designated as a mosaic. If an individual lacks parts of the antigen, he or she may make antibodies to the missing parts if exposed to the whole D antigen.
What does the genotype —/— represent in the Rh system?
a. Rh negative
b. D mosaic
c. Rh null
d. Total Rh
c. Rh null
A person who is Rh null shows no Rh antigens on his or her RBCs.
What techniques are necessary for weak D testing?
a. Saline + 22°C incubation
b. Albumin or LISS + 37°C incubation
c. Saline + 37°C incubation
d. 37°C incubation + indirect antiglobulin test
d. 37°C incubation + indirect antiglobulin test
Weak D testing requires both 37°C incubation and the IAT procedure.
Which of the following sugars must be present on a precursor substance for A and B antigenic activity to be expressed?
a. D-Galactose
b. N-Acetylgalactosamine
c. Glucose
d. L-Fucose
d. L-Fucose
Without H substance present, the sugars giving A or B antigenic activity cannot attach.
Lectins are useful in determining the cause of abnormal reactions in blood bank serology. These lectins are frequently labeled as anti-H, anti-A1 etc. The nature of these lectins is explained by which of the following?
a. An early form of monoclonal antibody produced in nonvertebrates
b. A plant substance that chemically reacts with certain RBC antigens
c. Naturally occurring antibodies in certain plants
d. The ability of plants to respond to RBC antigens by antibody production
b. A plant substance that chemically reacts with certain RBC antigens
Lectins are proteins present in plants, often derived from the seeds of plants.
If a patient has the Rh genotype DCe/DCe and receives a unit of red blood cells from a DCe/dce individual, what Rh antibody might the patient develop?
a. Anti-C
b. Anti-c
c. Anti-d
d. Anti-E
b. Anti-c
The unit from the DCe/dce donor has the c antigen that the patient lacks.
Which of the blood group systems is associated with antibodies that are generally IgM?
a. Rh
b. Duffy
c. Kell
d. Lewis
d. Lewis
Lewis system antibodies are generally IgM.
In which of the following blood group systems may the red blood cell typing change during pregnancy?
a. P
b. MNS
c. Lewis
d. Duffy
c. Lewis
The Lewis typings of a pregnant woman may appear to be Le(a-b-), even though the original typing may have been Le(a-b+).
All are associated with Group I ABO discrepancies, except:
a. Newborns and elderly patients
b. Patients with congenital immunodeficiency diseases
c. Patients using immunosuppressive drugs
d. Subgroups of A or B
d. Subgroups of A or B
An antigen present on most D-positive and all C-positive RBCs:
a. G
b. f
c. rhi
d. Cw
a. G
From the following ABO mating, what are the probabilities of the ABO PHENOTYPES of potential offspring? Mother: Group O; Father: Group B (heterozygous).
a. 50% BO, 50% OO
b. 100% BO
c. 50% B, 50% O
d. 50% B, 50% A
c. 50% B, 50% O