Blood Bank Extra Credit Exam 1
On which chromosome are the genes that code for Rh proteins, namely, RhD and RhCE located?
1
The Rh gene is located on which chromosome?
1
Approximately how many antigen sites exist on a Type-A1 Individuals RBC?
1 million
How many IgG molecules must be present on the red blood cell for a positive IAT to occur?
100
What percentage of the Type A Population is A2?
20%
Approximately what percentage of the black population is [Le(a-b-)]?
22%
At what temperature do IgM antibodies react?
22C
Approximately how many antigen sites can be found on A2 Cells?
260,000
What is the incubation time for the IAT when saline is used instead of LISS?
30 minutes
What is the frequency of E antigen in the general population?
30%
At what temperature do IgG antibodies react optimally?
37C
At what temperature is the incubation phase of the AHG test?
37C
What is the optimal temperature for complement activation?
37C
All of the following is consistent with A3 individuals except:
4,000 antigenic sites on red blood cells
At what age do infants begin to produce their own antibodies?
4-6 months
What percentage of the white population has Type-O Blood
45%
What percentage of A2 individuals produce Anti-A1
5%
Saline used for blood banking tests should have a pH of __________.
7.2-7.4
What percentage of individuals inherit the secretor gene?
80%
What percentage of the Type-A population are A1?
80%
The Rh antibody agglutinates what percentage of RBCs?
85%
What percentage of the white population inherits the Le gene?
90%
All of the following is true regarding formation of the ABH Antigens except:
A Type 1 Structure refers to a beta 1-2 linkage
Which of the following reagents or methods is best for categorizing partial D types?
A combination of serological typing and molecular analysis
What does hemolysis represent in an antigen-antibody reaction?
A positive result
What ABO group contains the least amount of H substance?
A1B
All of the following testing is available that will differentiate between a true B and an acquired B EXCEPT:
A2 Cells
Mixed field agglutination encountered in ABO forward grouping may be caused by:
A3
Reverse grouping showed negative reactions with A1 and B Cells. Forward grouping showed positive reactions with A, B, and AB antisera. What blood type is consistent with these results?
AB
Which ABO Group's reaction will be the weakeast with Anti-H Lectin?
AB
An AB Male mates with an AB female. What could be the genotype of the offspring?
AB, AA, and BB
What other consideration should be made before beginning a subgroup investigation?
ABH alteration caused by malignancy
Which blood group antibodies are known to activate complement, leading to intravascular hemolysis?
ABO
When a patient has Rh-null syndrome, what kind of packed RBCs need to be transfused?
ABO Compatible Rh-Null Blood
Which of the following is not a characteristic of antibodies within the ABO system?
ABO antibodies do not activate complement
What substances are found in a Group A secretor?
AH
In the Fisher-Race nomenclature, "d" refers to all except?
Absence of D
Serum from a Group B individual contains Anti-A1. When A2 cells are added to serum and centrifuged, the cells with attached Anti-A are removed from serum. What is the name of this technique?
Absorption
A patient who was recently diagnosed with an obstructed bowel became septic from Proteus vulgaris. Prior to surgery, a routine type and screen was performed. Though this person typed as an A 2 years ago, his forward type is consistent with an AB individual, albeit weaker in strength with anti-B. What is the reason for this discrepancy?
Acquired "B"
What test is used to remove autoantibodies from test serum?
Adsorption
Anti-LW will react most strongly with:
Adult Rh-Positive RBCs
Which of the following criteria is NOT used to classify the B Subgroups?
Agglutination with A1 Lectin
Why is determination of Rh status crucial for obstetric patients?
All Rh-Negative Mothers are possible candidates for Rh immune globulin
Which of the following are produced after exposure to genetically different non-self antigens of the same species?
Alloantibodies
If a Group O mother gives birth to a Group A baby, which of the following antibodies is usually responsible for crossing the placenta and causing hemolytic disease of the newborn (HDN)?
Anti-AB
Rh-Immune globulin is effective in preventing which type of hemolytic disease of the newborn (HDN)?
Anti-D
Which of the following statements is false?
Anti-D usually stimulates complement
Polyspecific AHG contains
Anti-IgG Anti-C3d
What does polyspecific AHG contain?
Anti-IgG, -C3b, -C3d
Which of the following statements regarding Anti-LW is true?
Anti-LW reacts stronger with Rh-Postive cells than with Rh-Negative Cells
Why is reverse grouping not performed on cord blood specimens?
Antibodies are generally not present at birth
The Del Phenotype is most commonly found in individuals of which ethnicity?
Asian
Secretor studies were performed on a person who expressed weak reactions in forward grouping. Only B and H substance were present in the saliva. What is this person's ABO Group?
B
What is the source of Anti-B Lectin?
Bandeiraea Simplicifolia
What does the type 1 chain refer to?
Beta linkage of the number 1 carbon of galactose to the number 3 carbon of N-acetylglucosamine residue or precursor structure
In which population is the genetic Du usually found?
Black
Individuals with Group B Blood are more common among which populations?
Black/Asian
In preparing anti-IgG how is excess antibody removed for titer adjustment?
Block Titration
What does the hh genotype refer to?
Bombay
How is the classical pathway of complement activated?
By binding of antigen with antibody
Which of the following Rh phenotypes invites Cw antigen testing?
C+c-
G Antigen is present on all of which type of red blood cells?
C-Positive
All of the following complement proteins can be found on the red blood cell membrane except:
C4a
Why is EDTA not conducive to complement activation?
Calcium is inactivated
The biochemistry structure of the Rh antigens is a nonglycosylated protein, meaning:
Carbohydrates are not attached to protein structure
What MHC Class encodes complement components?
Class III
A patient was previously typed as Blood Group O. Forward grouping was negative with Anti-A and Anti-B. Reverse grouping showed reactivity with A1 cells and B cells. The technologist reported this patient's type as A. What technical error occurred?
Clerical Error
How are the Rh antigens inherited?
Codominant alleles
The antihuman globulin (AHG) test was discovered in 1945 by whom?
Coombs
All of the following may depress antigen expression except:
Coronary Heart Disease
Conventional tube testing in AHG testing has one distinct advantage over gel testing. Identify the advantage:
Cost
The antigen ceCF is known as:
Crawford Antigen
Which of the following Rh antigens is the most immunogenic?
D
What immunodominant sugar is responsible for B Specificity?
D-Galactose
Which of the following genotypes would demonstrate the strongest expression of D antigen?
DCe/dce
Which gene combination is expressed in the greatest frequency in the black population?
Dce
Which of the following genotypes is consistent with f antigen expression?
Dce/DCE
Forward Grouping is defined as:
Detecting antigen(s) on an individual's red blood cells via reagent antisera
Only 5% of Kell-Negative individuals will develop antibodies to Kell if exposed to the Kell antigen, whereas 50% to 70% of Rh(D)-Negative Individuals would produce antibodies to D upon exposure. What is the reason for this?
Difference in immunogenicity
What is the most important use for Anti-B Lectin?
Differentiating a true B from an acquired-like B
What function does chemically modified IgG serve?
Disulfide bonds are reduced in the hinge region of IgG, which promotes flexibility of Fab portions
What is the source of Anti-A1 Lectin?
Dolichos Biflorus
All of the following are important in evaluating a positive DAT except:
Donation History
A person with the genotype MM shows a 3+ reaction when red blood cells are mixed with M antisera, whereas a person with the genotype MN shows a 1+ reaction. What phenomenon is occurring here?
Dosage
Which antigen represents Rh3 in Rosenfield Terminology
E
All of the following techniques are used in the laboratory to detect blood group antigens or antibodies except?
ELISA
What is a possible consequence of incubating tubes too long with LISS when performing the IAT?
Elution of antibody from red blood cells
What effect does a low pH have on a saline AHG Test?
Enhances antibody elution
What is the cause of polyagglutination in most cases?
Exposure of T Antigen caused by bacterial contamination
All of the following are technical errors that could result in ABO discrepancies except:
Failure to warm reagents
Anti-IgG is specific for what part of the IgG molecule
Fc Fragment
Persons who inherit the Se and Le genes will have _______ A or B glycolipids in plasma than persons who are Se le.
Fewer
Lewis cell-bound antigens absorbed from plasma onto the red blood cell membranes are:
Glycolipids
What is the biochemical structure of secreted A, B, and H substances?
Glycoprotein
Red blood cells that phenotyped as [Le(a-b-)] are incubated with plasma containing Lea substance. The red blood cells convert to the phenotype [Le(a+b-)]. Whereas the same red blood cells incubated with saliva containing Lea substance do not convert. Why?
Glycoproteins are not absorbed onto red blood cell membranes
What substance must be formed first before A or B specificity is determined?
H
Which antibodies characteristically demonstrate a decreased avidity for antigen?
HTLA
Which of the following is not a clinical application for a direct antiglobulin test?
Heterophile Detection
What clinical manifestation may NOT be associated with the Rh-null syndrome?
High Hemoglobin
Which IgG antibodies are contained in polyspecific AHG?
High titer, high avidity
All of the following are characteristics of a secondary immune response except:
Higher dose of antigen required to form antibodies
How is polyclonal antiglobulin serum made?
Human serum is injected into rabbits, and an immune response triggers the production of an antibody
All of the following may result in weak or missing antigens except:
Hypogammaglobulinemia
A patient is discovered to have anti-Fya in their serum. The medical laboratory scientist needs to phenotype the patient's cells for the corresponding antigen. What test is appropriate for phenotyping?
IAT
Most Rh antibodies are of what immunoglobulin class
IgG
What class of immunoglobulin is capable of crossing the placenta?
IgG
Which of the following antibodies is considered the most significant in blood banking because it reacts at body temperature?
IgG
Most clinically significant blood group antibodies are of which IgG subclasses
IgG1 IgG3
Which IgG subclass primarily comprises antibodies to the Rh blood group system?
IgG1, IgG3
Which IgG subclasses carry the most significant with regard to Rh antibodies?
IgG1/IgG3
Anti JK (Kidd) antibodies are of what class of antibody?
IgG3
"Complete" agglutinins that agglutinate red blood cells in saline are of which immunoglobulin class?
IgM
Anti-A from a Group B Individual is primarily what class of immunoglobulin?
IgM
All of the following are true regarding IgM antibodies except?
IgM antibodies form against Kell
If not labeled "gamma heavy chain-specific", monospecific anti-IgG may contain antibodies to:
Immunoglobulin Light Chains
Why is incubation omitted in the direct AHG Test?
In Vivo antigen antibody complex is already formed
The indirect antiglobulin test detects which antigen-antibody reactions?
In vitro
A patient came in for a routine type and screen prior to surgery. The antibody screen was negative at 37C and at the AHG phase. Check cells did not produce agglutination often. What is a possible explanation for this result?
Inadequate washing
When there is an excess of antigen in a serologic test system, what course of action should be followed?
Increase the serum-to-cell ratio
Which of the following may be a possible cause for the lack of expression of Lewis Antigens during pregnancy?
Increased ratio of plasma lipoproteins to RBC mass
An elderly patient is documented as being Type O. The forward grouping is negative with Anti-A and Anti-B. The reverse grouping shows no reactivity with A1 cells and B Cells. What can be done to correct the discrepancy?
Incubate the patient's serum and reagent cells for 15 minutes at room temperature
All of the following statements regarding the AHG test are true except:
Incubation time with LISS should be a minimum of 30 minutes
All of the following may occur following an Rh-mediated hemolytic transfusion reaction except:
Intravascular Hemolysis
What is the purpose of the antihuman globulin (AHG) test in blood banking?
It detects red blood cells coated with antibody by bridging the gap between red blood cells
What is an advantage of using chemically modified Anti-D?
It provides a low-protein medium
Which of the following antibodies is least likely to bind complement?
Kell
What immunodominant sugar is responsible for H specificity?
L-Fucose
Persons who inherit the h allele do not produce ______________ transferase necessary for formation of the H Structure.
L-Fucosyl
Which of the following indicates secretor gene control overproduction of H substance?
L-Fucosyltransferase is found in the saliva of secretors
All of the following are tests performed in the blood bank to classify subgroups of A except:
LISS Enhancement
In an immune response, what is the time called during which no antibody is detected in the test serum?
Latency Period
An individual from Bombay who has inherited the Le gene will have a phenotype of:
Le(a+b-)
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-) Nonsecretor
Pregnant women usually express which phenotype?
Le(a-b-)
All of the following may result in rouleaux formation except:
Leukemia
Which of the following blood group systems is not likely to cause HDN?
MN
Which of the following is consistent with hemolytic disease of the newborn (HDN)?
Maternal antibody coating fetal red blood cells
What cells are responsible for mounting a secondary response when exposure to the same antigen occurs?
Memory T/B Cells
Which of the following is not true of monoclonal reagents?
Monoclonal reagents are produced for single antigens with more than one epitope
IgG-Coated RBCs will be phagocytized by what effector cells?
Monocytes/Macrophages
What are the dangers of transfusing donor Rh-Negative RBCs to an Rh-Positive patient?
Most Rh-Negative blood is c- and e pos, and because of their immunogenicity the patient may form an antibody to those antigens
Individuals who are Le(a-b-) and can develop Lewis Antibodies without exposure to Lewis Antigens are called:
Naturally Occuring
The ABO Group antibodies are primarily
Naturally occuring
If a Type-A person contains Anti-M in his or her serum, what might the reverse grouping type as?
O
The forward grouping of a patient showed no agglutination of patient cells with Anti-A, Anti-B, or Anti-AB reagent antisera. The reverse grouping showed agglutination with A1 and B Cells. What is this person's ABO Group?
O
What is the only possible phenotype of an offspring produced from two group O parents?
O
Which blood group contains the highest concentration of H Antigen?
O
A1 Lectin Agglutinates
Only A1 Cells
Why is the 37C reading omitted when using PEG additive?
PEG may cause aggregation of RBCs at 37C
What is used to stimulate saliva secretion in secretor studies?
Paraffin Wax
Of the three following categories of altered D antigen, in which variation of D antigen expression are you more likely to encounter an allo-anti-D?
Partial D
When one or more D epitopes within the entire D protein is missing it is termed ______________
Partial D
How is polyagglutination resolved?
Patient Cells are tested with a lectin panel
A type-A person demonstrates a 3+ reactivity with A1 cells (reverse grouping). The forward grouping with anti-A is 4+. Therefore, the possibility of a subgroup is excluded. B cells demonstrate a 4+ reaction. The antibody screen is weakly positive at 37°C but shows no reactivity at the AHG phase. An antibody panel is performed and anti-M is identified. The patient phenotypes negative for M antigen. How is the ABO discrepancy resolved?
Perform reverse grouping with A1 Cells Negative for M Antigen
That state in which an individuals red blood cells are agglutinated by all sera regardless of blood type is called:
Polyagglutination
An advantage of polyclonal anti-IgG over monoclonal anti-IgG is:
Polyclonal anti-IgG will recognize IgG variants
Why is it important to use polyspecific AHG rather than monospecific
Polyspecific AHG is better at detecting IgG antibodies
What is NOT a possible explanation for a weak reaction (1+) in reverse ABO grouping test?
Positive DAT
What does the "R" represent in Wiener terminology?
Presence of D Antigen
How are ABH Antigens formed?
Production of specific glycosyltransferases add sugars to precursor substances
A Group O person with warm autoimmune hemolytic anemia may demonstrate weak reactions in the forward grouping due to:
Red Blood Cells being coated with antibody
What is the action of PEG?
Removes water molecules, thereby concentrating antibody
An anitbody screen is performed, and all three tubes are negative after adding AHG. Check cells are added, and the tubes are centrifuged. No agglutination occurs after the addition of check cells. What is the next course of action?
Repeating the antibody screen
Extravascular hemolysis occurs when red blood cells are coated with anitbody; what organ sequesters these cells?
Reticuloendothelial System
Two drops of serum are added to one drop of A1 Cells, and two drops are added to one drop of B Cells; the two tubes are centrifuged. The tubes show reactivity when read macroscopically. This is an example of:
Reverse Grouping
Where will the ABO discrepancy occur in cis-AB Individuals?
Reverse Grouping with B Cells
A cord blood sample was sent to the blood bank for a type and DAT. Cells were washed six times with saline before testing. The forward grouping typed as an O. There was no agglutination with anti-D and washed cord cells. The DAT was 3+ with polyspecific AHG. What is the Rh type of the baby?
Rh Type cannot be determined
All of the following are true regarding Rh antibodies except:
Rh antibodies can bind complement on the red blood cell membrane
What does Rh genotype refer to?
Rh genes inherited from both parents
What do "check cells" contain?
Rh(D)+ red blood cells coated with Anti-D
What Rh type does a mother have to be to produce antibodies to Rh(D) from an Rh-Positive infant?
Rh-Negative
The Rh testing on a blood donor was negative at immediate spin. The tube was incubated at 37°C for 15 minutes. The tube was centrifuged and read macroscopically. The test was negative at 37°C. The tube was washed three times with saline, and two drops of AHG were added. After centrifugation, the tube yielded a 2+ reaction. How is this Rh type reported on the donor unit?
Rh-Positive
All of the following may cause a false-negative reaction in Rh typing except:
Rouleaux
What protocol is put in place to validate Rh testing when high-protein reagents are used, especially when the patient types as an AB positive?
Run a control with Rh test?
Reverse Grouping was performed on an AB person. The technologist observed a very weak agglutination macroscopically. The cells appeared as "stacked coins" under a microscope. Which reagent should be added to the tube before recentrifugation in an attempt to resolve the discrepancy?
Saline
A patient with multiple myeloma exhibits rouleaux formation in an immediate spin crossmatch. What procedure is recommended to distinguish true red blood cell agglutination from nonspecific agglutination?
Saline Replacement
When performing secretor studies, what is omitted in the control tube but present in the patient tube?
Saliva
What is a lectin?
Seed extracts that agglutinate human cells with moderate specificity
You are performing an IAT, and you are suspicious of the results. It appears there may be a weak alloantibody present. You decide to repeat the test, and at the LISS stage you decide to add an extra two drops of serum to each tube being tested. What can you expect to happen?
Sensitivity of the test decreases, because you increased the ionic strength of the mixture
When antigen and antibody combine, they are held together by noncovalent forces. With the absence of a visible lattice, this stage is called ________.
Sensitization
Why are enzymes used in blood banking?
Sialic Acid is released from red blood cells, which helps to reduce the zeta potential
What does the term exalted D refer to?
Stronger expression of D antigens when Cc and Ee are missing
An individuals of the dce/dce genotype given dCe/dce blood has an antibody response that appears to be anti-C and anti-D. The most likely explanation for this is:
The antibody is Anti-G
What does the term zeta potential mean?
The attraction of negative charges on the surface of red blood cells to positive charges in an ionic cloud
A male patient was seen in the emergency room with an acute bleed. The recommendation from the blood supplier is to give O-positive RBCs as uncrossmatched blood. This patient has already been exposed to Rh-positive blood after a previous accident. What is a possible outcome?
The patient may have a hemolytic transfusion reaction from an allo-immunized Anti-D
If an individual with a partial D expression is transfused with a normal Rh-Positive unit of blood, a likely result will be:
The patient will form an antibody to the portion of Rh(D) protein that they are missing.
An agglutination inhibition test is performed on a person whose blood type is A+. The person's saliva is mixed with type A Antisera. After incubation, the solution is mixed with reagent A cells and no agglutination occurs. What can be deduced from this finding?
The person is a secretor of A substance
What is the basis of Rosenfield Rh terminology?
The positive (+) or negative (-) sign demonstrates the presence or absence of antigen on a red blood cell.
All of the following statements are true concerning ABH soluble substances except:
The precursor chain is type 2 (beta 1-4 Linkage)
Why can Anti-H sometimes be found in an A1B individual?
The specific immunodominant sugar blocks the presence of H Antigen
How would a negative IAT be demonstrated in solid phase methodology?
There is a pellet at the bottom of the well
All of the following statements are representative of Lewis Antibodies except:
They are destroyed by enzymes
Which is a characteristic of natural killer (NK) cells?
They bind to and lyse antibody-coated cells in ADCC
Why are check cells added to all negative reactions in the AHG test?
To ensure AHG was not neutralized by free globulin molecules
What is the purpose of washing cells in the AHG Test?
To remove all unbound protein
In the production of polyspecific AHG, why are IgG and complement antibodies absorbed with A1, B, and O Cells?
To remove heterospecific antibody
What is the source of Anti-H Lectin?
Ulex Europaeus
All of the following are characteristics of monoclonal reagents except:
Undetectable subgroups of A
What is responsible for recognition of the antibody-binding site to homologous antigen?
Variable region of light/heavy chain
Antibody titers specific to Antigens from the ABO System are typically highest:
When the patient is around 10 years old
An advantage of monoclonal Anti-C3 over polyclonal anti-C3 is:
With monoclonal Anti-C3, the antibody potency can be controlled
In the black population, a mosaic form of which antigen may be found?
e
