Blood bank Reviewing Concepts 1-5
What percentage of the group A population are type A2?
20%
What substances are found in the saliva of a group A person who also inherited the secretor gene?
A, H
Which of the following red cell antigens do proteolytic enzymes destroy?
Antigens Fya and Fyb in the Duffy system
ry
CE
N-acetylgalactosamine
Group A
Which ABO phenotype selection contains the most H antigen and the least H antigen, respectively, on the red cell's surface?
O, A1B
A patient phenotypes as D+C+E-c-e+. The most likely genotype is:
R1R1
How is RNA different from DNA?
RNA usually exists as a single strand. The sugar ribose is substituted for deoxyribose. The base uracil exists only in RNA
In the solid-phase red cell adherence test, a negative test would appear as:
a button of cells on the bottom of the well
A person whose red cells type as M+, N+ with antisera would be:
a heterozygote (Feedback: Because M and N are alleles, the inheritance of both alleles makes the individual a heterozygote)
Polyspecific antihuman globulin contains:
anti-IgG and anti-C3d
rr
ce
Select the portion of the antibody molecule that imparts the antibody's unique class function.
constant region of the heavy chain
The frequency of the D-negative phenotype in the population is:
15%
Following centrifugation of the gel card, red cells are observed to be evenly dispersed throughout one of the microtubes. This reaction could be graded as a:
2+
The indirect antihuman globulin test is incubated at what temperature?
37C
After adding antigen and antibody to a test tube, one large agglutinate was observed. How should this reaction be graded?
4+
Approximately what is the percentage of individuals who demonstrate H in their saliva?
80%
Why is the determination of the D antigen important for women during pregnancy?
A D-negative mother should be given Rh Immune Globulin to prevent potential formation (Feedback: D-negative females that are pregnant should be Rh Immune Globulin at 28 weeks to prevent the formation of anti-D, which may cause hemolytic disease of the fetus and newborn on subsequent pregnancies. The exposure to the D antigen on delivery of a D-positive fetus triggers the formation of anti-D. of anti-D during delivery of a D-positive infant)
What ABO phenotype would agglutinate in the presence of anti-A,B produced by group O individuals?
A and B (Feedback: Group O individuals make anti-A,B, an antibody with a specificity to both the A and B antigens)
What is meant by the term autosomal?
A trait that is not carried on the sex chromosomes (Feedback: Autosomal genetic expression is demonstrated in somatic cells, that is, cells in the body that are not gametes)
Reagent used in the identification of ABO antibodies
A1 and B cells
A recipient with group A phenotype requires a transfusion of 2 units of frozen plasma. Which of the following types are appropriate to select for transfusion?
AB and A
Reagent used to determine the ABO antigenic composition of a patient's red cells
ABO antisera
The test procedure that combines patient's serum with commercial A1 and B reagent red cells is called:
ABO reverse grouping
In a family study it was determined that all four siblings in the family had a different blood type: A, B, O, and AB. The parents were most likely ____________.
AO and BO (Feedback: Performing a Punnett square demonstrates that a cross between genotypes AO and BO could yield four offspring with different phenotypes)
The subgroup of A with the least amount of A antigen is:
Ael (Feedback: The Ael subgroup requires adsorption and elution procedures to detect the A antigen on the red cells)
A gene that does not express a detectable product
Amorphic genes
Amplified target sequences of DNA produced by polymerase chain reaction
Amplicon
What forward typing reagent can be used to confirm group O units before placing them in inventory?
Anti-A, B
According to Landsteiner's rule, what ABO antibody will be detected in a group A individual's serum?
Anti-B
Which of the following is responsible for the activation of the classic pathway of complement?
Antibody bound to antigen
How is it genetically possible for a child to phenotype as D-negative?
Both parents are heterozygous D-positive
Select the cell involved in the clearance of viral infected cells, tumor cells, and foreign-tissue grafts.
CD8 cells
r'
Ce
Equal expression of two different inherited genes as in most blood group systems
Codominant genes
Of the following markers that can be used to test for paternity, which marker provides the most useful statistical value? A) Human leukocyte antigen typing B) D antigens C) ABO system antigens D) The Kidd system (Jka, Jkb)
D antigens
How would a donor who tested negative with anti-D reagent in the immediate spin test but positive at antihuman globulin with anti-D reagent be labeled?
D-positive
The LW antigen expression is typically stronger on __________ cells.
D-positive red
Rz
DCE
R1r
DCce
R1R1
DCe
R2R2
DcE
R0
Dce
Incubation step is not necessary
Direct antiglobulin test
tests for certain clinical conditions such as hemolytic disease of the newborn and autoimmune hemolytic anemia
Direct antiglobulin test
To distinguish between an A1 and A2 blood type, which reagent is used?
Dolichos biflorus lectin (Feedback: A1 lectin will agglutinate A1 red cells, not A2 red cells)
Parents who are both phenotyped as group A cannot have a group O child True or False
False
What portion of the antibody molecule binds to receptors on macrophages and assists in the removal of antibody bound to red cells?
Fc fragment
A group A man marries a group AB woman. The father of the group A man was group O. What possible ABO phenotypes could be expected in the offspring?
Group A, B and AB
A patient's red cells are agglutinated by anti-B, but not by anti-A. This person would have which of the following ABO phenotypes?
Group B
D-galactose
Group B
Which of the following situations is most likely to cause intravascular hemolysis when an incompatible transfusion is given?
Group B packed cells to a group O recipient
Given the following ABO phenotyping data: FORWARD Anti-A: 2+mf Anti-B: 0 REVERSE A1 Cells: 0 B cells: 3+ What could be a plausible explanation for this discrepancy?
Group O blood products given to group A (Feedback: Mixed-field reactions are often caused by transfusion of group O red cells, which may take place during an emergency or inventory issue)
L-fucose
Group O, H antigen
When two genes are close together on the same chromosome and are inherited as a "group" or "bundle," they are inherited as this
Haplotypes
Select the term that is associated with the B-cell response to antigens
Humoral immunity
The binding of two complementary pairs of DNA
Hybridization
Most Rh system antibodies are of which immunoglobulin class?
IgG
What immunoglobulin class is capable of crossing the placenta?
IgG
What immunoglobulin class reacts best by antiglobulin testing?
IgG
What immunoglobulin class reacts best at room temperature at immediate spin?
IgM
Most "naturally occurring" ABO system antibodies fall into which class?
IgM (Feedback: ABO system antibodies are in the IgM class, which can agglutinate at immediate spin and activate the complement cascade)
Select the appropriate strategy if the results of red cell and serum testing in the ABO typing procedure have negative agglutination reactions.
Incubate tubes at room temperature or 4C with an autocontrol (Feedback: ABO antibodies are stronger at room temperature or lower. The autocontrol determines whether the enhanced antibody reaction was due to the ABO antibodies or to a cold reacting antibody. The autocontrol should be negative for the ABO typing to be valid)
Reagent derived from plants used to distinguish group A1 from group A2 red cells
Lectins
Select the cell involved in acquired immunity.
Lymphocytes
What cells are also known as antigen-presenting cells
Macrophages
What would be the agglutination reaction of red cells from a Bombay phenotype with anti-H lectin?
Negative
Dose Bombay have immunodominat sugar?
No, none
The children of an AB mother and a B father could phenotype as all of the following except:
O (Feedback: Unless there was a rare cis AB inheritance pattern, an AB parent would not likely have a group O child)
Reagent to identify the specificity of a red cell antibody
Panel cells
Technique used to replicate a specific targeted DNA sequence
Polymerase chain reaction
Having two or more alleles at a given gene locus,
Polymorphic
Short segment of DNA with a known sequence that can be labeled with a marker
Probe
h of the following genotypes is possible for an individual whose red cells react as indicated below except: ANTISERA REACTIONS anti-C + anti-D + anti-E + anti-c + anti-e +
R0r" (Feedback: The R0r' genotype expresses the C, c, D, and e antigens, but it does not express the E antigen)
When a gene product is expressed only when it is inherited by both parents
Recessive
DNA fragments produced by enzymatic cleavage at specific recognition sites
Restriction fragment-length polymorphism
Current theory regarding the genetics of the Rh system suggests that:
Rh system antigens are coded by two closely linked genes
Reagent to detect the presence of red cell antibodies
Screening cells
The evidence for reagent red cell deterioration may include which of the following?
Spontaneous agglutination, significant hemolysis, loss of agglutination strength over time
Why is incubation omitted in the direct antihuman globulin test?
The antigen-antibody complex has already formed in vivo
When using the Hardy-Weinberg equation to calculate genetic frequencies, which of the following must be true?
The population statistics must be large. Mutations cannot occur. Mating must be random
Which of the following statements is true regarding high-protein anti-D reagents?
They have been largely replaced with low protein monoclonal reagents. They contain approximately 20% bovine albumin. They may increase the possibility of a false-positive reaction, requiring the use of a control.
Why is it sometimes necessary to distinguish A1 and A2 blood types?
To resolve a discrepancy between the forward and reverse typing (Feedback: Routine testing with anti-A1 lectin is necessary to resolve a discrepancy between the forward and reverse typing. Individuals who possess the A2 antigen can make anti-A1 antibody)
Anti-D reagent and the Rh control were tested with red cells. Both tests were 2+ agglutination reactions. What is the interpretation of the results?
Unable to interpret without further testing
A father carries the Xga blood group trait and passes it on to all of his daughters but to none of his sons. What type of inheritance pattern does this demonstrate?
X-linked dominant (Feedback: Because the father passed the trait to only his daughters, it was carried on the X chromosome. Because only one is needed for expression, this is a dominant genetic trait)
An advantage of the polymerase chain reaction for viral marker testing is:
a small amount of DNA or RNA can be detected
The weak D test detects:
a weak D antigen
An advantage of using a monoclonal antibody over a polyclonal antibody includes all of the following except:
all variations of the antigen can be detected
An antibody with a specificity other than to one's own cells or tissue that is stimulated by transfusion or pregnancy is termed an:
alloantibody
An anti-E was identified in a patient who recently received a transfusion. What other Rh system antibody should be investigated
anti-c (Feedback: Anti-c is often found in patients who make anti-E. Anti-c is often weaker and shows dosage when the patient is developing the antibody from the first exposure to the antigen)
In a serologic test, the term prozone is also known as:
antibody excess
Select the test that uses IgG-sensitized red cells (check cells).
antiglobulin test
In a lymphocytotoxicity test, cells that take on the dye:
are recognized by a specific antibody
Detect IgG or complement-coated red cells
both the direct and indirect antiglobulin test
Requires washing the cells several times before the addition of antihuman globulin reagent
both the direct and indirect antiglobulin test
The numeric Rh4 nomenclature refers to which antigen in the Rosenfield notation?
c (Feedback: The more common Rh system antigens are Rh1 = D, Rh2 = C, Rh3 = E, Rh4 = c, Rh5 = e)
The purpose of adding antibody-sensitized red cells following the antiglobulin test is to:
check that the wash procedure was sufficient to remove unbound antibodies
The inheritance of the Rh antigens are:
codominant
What is the potential effect in a tube agglutination test if a red cell suspension with a concentration greater than 5% is used?
false negatives
Select the method that uses a dextran-acrylamide matrix.
gel technology
The major histocompatibility complex is located on chromosome 6 and is important in all the following immune functions except:
hemolysis
All of the following can cause the D antigen expression to be weaker except:
inheriting the G gene (Feedback: The G gene is always inherited when the D or C gene is inherited and has no effect on the strength of the D gene)
The gel technology method uses a concentration of red cells that is:
lower than tube techniques
Crossing over occurs during:
meiosis (Feedback: Crossing over is the sharing of chromosomal material during meiosis and contributes to greater genetic variation among offspring)
Testing for the weak D expression is performed by:
performing the indirect antiglobulin test with anti-D (Feedback: The weak D test (previously called the Du test) involves the indirect antiglobulin test using anti-D reagent)
When an individual is said to be group A, it refers to the individual's:
phenotype
Reagent antibodies prepared from human sources are:
polyclonal in specificity
What reagent contains antibodies to multiple antigenic epitopes?
polyclonal-based
Which red cells are used to screen for antibodies in donor samples?
pooled screening cells
Product limitations and technical considerations for each reagent can be found in the:
product insert
Human leukocyte antigen antibodies are often stimulated following a patient's repeated transfusions of platelets. This poor response to platelet transfusion is known as:
refractoriness.(Repeated platelet transfusions that contain leukocytes can increase the immune response to human leukocyte antigen and decrease the effectiveness of platelet transfusion.)
Which of the following phenotypes will react with anti-f?
rr (Feedback: The f antigen is the expression of the c and e gene complex when they are inherited on the same chromosome. Because the Weiner nomenclature "r" indicates that the ce gene was inherited together, it will express the f antigen)
Which of the following will cause an antigen to elicit a greater immune response?
size greater than 10,000 daltons
The antiglobulin test was performed using gel technology. A button of cells was observed at the bottom of the microtube following centrifugation. This result indicates a:
strong positive reaction
A blood sample from a 90-year-old man was submitted to the blood bank for a type and screen before surgery. The forward type demonstrates as a group A, whereas the reverse type appears to be group AB. The most likely cause of the discrepancy is:
that patient has low-titer isoagglutinins (Feedback: In patients who are older, the level of ABO isoagglutinins can be below detectable levels)
Solid-phase red cell adherence used for antibody detection has an advantage over tube testing because:
the endpoint is more clearly defined
If two traits were found to occur higher in a population together than each occurs separately, they may be linked. This would suggest that:
the genes are close together on the same chromosome
Red cells that phenotype as D-negative indicate that:
there is no genetic material inherited from the RHD gene from both parents (Feedback: The D-negative phenotype is caused by the absence of genetic material at the RHD gene locus. This must be inherited from both parents to result in a negative expression)
Which of the following statements is true regarding IgG-sensitized red cells?
they must be used to confirm a negative antiglobulin tube test
Mitosis results in __________ chromosomes as the original.
two cells with the same number of
How would you interpret the results if both the anti-D reagent and the Rh control were 2+ agglutination reactions?
unable to determine without further testing
Select the region of the antibody molecule responsible for imparting unique antibody specificity.
variable region
Monoclonal antibodies are prepared in:
vitro (Feedback: Monoclonal antibodies are prepared from antibody-producing B lymphocytes and myeloma cells in a hybridoma)
If anti-M was reacted with red cells that are M+N+, how would they compare with red cells that are M+N-?
weaker
