What would be the laboratory findings in a patient with a partial D phenotype? - Correct Answer Patient
cells will react weakly to reagent anti-D antibody
What is the pathogenesis of alloanti-D antibodies in patients with a partial D phenotype? - Correct
Answer Patients lack certain antigenic components on their own D antigens, so they make anti-D to any
red cells that express the full D protein.
Give some reasons why a patient that expresses an Rh D phenotype may be found to have anti-D on
screening. - Correct Answer - Clerical error
- Partial D RBC phenotype
- Passive acquisition of anti-D from a red cell transfusion
- Autoagglutinins
What are the two most common causes of anti-D alloantibody? - Correct Answer Alloimmunization
through:
- Transfusion or
- Pregnancy
What percentage of D-negative patients will develop anti-D antibody if transfused with D antigen
positive red cells? - Correct Answer ~80%
How much plasma is included in a unit of packed red cells that is preserved with CPDA? - Correct Answer
In CPDA units: 50 mL
What is the frequency of the k antigen in the donor population? - Correct Answer - 98.8%
- -k antibody, only 0.2% of
donors will be compatible with this patient
,Are anti-M antibodies IgG or IgM? Are they normally clinically significant? - Correct Answer - Anti-M
tends to be IgG
- Even though they are IgG, they are most often cold reactive antibodies and are therefore clinically
insignificant
What is the Cobalt (Co) antigen? - Correct Answer It is found on the plasma membrane of red blood
cells and renal tubular epithelial cells. It is on a protein called aquaporin-1 (AQP1 gene product), which is
responsible for water homeostasis and urine concentration.
How frequent is the Co(a) antigen in the donor population? - Correct Answer - Found in 99.8% of donors
- Thus finding Co(b) or Co-null blood is very difficult
Are anti-Co(a) antibodies IgG or IgM? Are they normally clinically significant? - Correct Answer - Usually
IgG antibodies
- Can cause hemolytic transfusion reaction and HDFN
A post-transfusion blood sample has a positive DAT. What is the next appropriate procedure? - Correct
Answer An elution test should be performed to find the antibody specificity.
Possible reasons for a panreactive antibody on DAT. - Correct Answer - Warm autoantibody
- An antibody to a high incidence antigen
Is a DAT-positive donor unit likely to have clinically significant antibodies? - Correct Answer No, because
the antibodies bound to the donor red cells will stay bound in vivo in the recipient.
The reactivity of blood group A is confirmed by detecting the presence of which immunodominant sugar
molecule? - Correct Answer The A gene codes for production of N-acetylgalactosamine transferase, an
enzyme which binds N-acetylgalactosamine (GalNAc) to the H structure (L-fucose).
A mnemonic for remembering that the carbohydrate in blood group A is N-acetylgalactosamine. -
Correct Answer In my opinion, the best way to recognize the full sugar name is to remember the
abbreviation. GalNAc would likely point you towards something containing a "...gal..." in the answer. -
bbguy.org
,Why do individuals with the Bombay phenotype (O(h)) lack alloanti-O antibodies? - Correct Answer "O,
please remember, is not an antigen, it's the lack of A and B antigens, so anti-O is not a legitimate
antibody." -bbguy.org
Which cells agglutinate most strongly with Ulex europaeus lectin? - Correct Answer This particular
lectin, when tested against human red cells, closely parallels the reactivity we'd expect to see if we used
actual anti-H. The main blood groups agglutinate with the following relative strength with anti-H or Ulex
groups, but also have a molecular structure that leaves fucose very accessible to anti-H. As a result,
these cells agglutinate very strongly with Ulex.
What are some characteristics of naturally occurring (non-alloimmune) antibodies that distinguishes
them from alloimmune (transfusion-related) antibodies? - Correct Answer In short, naturally occurring
antibodies are generally of the IgM class, not able to cross the placenta, enhanced in reactivity by
incubation at 4C, and cause direct agglutination at room temperature.
ABOMNILS are red cell stimulated (not naturally occurring)
What ABH substances would be found in the saliva of a group B secretor? - Correct Answer H and B. The
secretor status of an individual (genotype SeSe or Sese) determines the formation of H antigen in
secretions, which in turn creates opportunity for A and B antigen formation, if either (or both) gene is
inherited
Can an individual of a secretor phenotype (genotype of SeSe or Sese) have O antigen in their secretions?
- Correct Answer No. There is no such thing as O antigen!
The ABO system is the most important blood group system in transfusion safety. Why? - Correct Answer
ABO is the only blood group system in which reciprocal antibodies are normally produced for the
antigens an individual lacks AND the ABO antibodies are capable of causing rapid, intravascular
hemolysis.
An ABO discrepancy between forward and reverse grouping owing to weak-reacting or missing
antibodies could be BEST explained by _____. - Correct Answer Patients with extreme ages (the very old
or the very young). In the very old and very young, the natural expression of isoagglutinins can either be
depressed or delayed, respectively
, What could be the cause of a missing red cell (forward) reaction type of ABO incompatibility? - Correct
Answer Group A subgroups often lead to missing red cell (forward) reactions
What could be the cause of an ABO discrepancy that results in an extra red cell (forward typing)
reaction? - Correct Answer Acquired B phenomenon results in extra red cell reactions
A blood donor has the genotype hh, AB. What is his apparent red cell phenotype during routine forward
and reverse group typing? - Correct Answer Type O. Without either the HH or Hh genotype, and the
resulting "H Structure," the A and B antigens inherited as part of the AB genotype are unable to attach
to the RBC membrane type 2 chains. Such an individual's red cells would appear as group O,
phenotypically.
-
Correct Answer About 80%
- Correct Answer Dolichos biflorus
duce naturally occurring (ie, immune) anti-
clinical significance of these antibodies? - Correct Answer Anti-
insignificant
Which genes codes for production of the same basic antigen as the H gene? - Correct Answer Secretor
(Se) gene
Color of anti-B reagent antibody - Correct Answer Yellow
Color of anti-A reagent anti-body - Correct Answer Blue
Which reagent antibody is in this bottle? - Correct Answer Anti-B
Which reagent antibody is in this bottle? - Correct Answer Anti-A
cells will react weakly to reagent anti-D antibody
What is the pathogenesis of alloanti-D antibodies in patients with a partial D phenotype? - Correct
Answer Patients lack certain antigenic components on their own D antigens, so they make anti-D to any
red cells that express the full D protein.
Give some reasons why a patient that expresses an Rh D phenotype may be found to have anti-D on
screening. - Correct Answer - Clerical error
- Partial D RBC phenotype
- Passive acquisition of anti-D from a red cell transfusion
- Autoagglutinins
What are the two most common causes of anti-D alloantibody? - Correct Answer Alloimmunization
through:
- Transfusion or
- Pregnancy
What percentage of D-negative patients will develop anti-D antibody if transfused with D antigen
positive red cells? - Correct Answer ~80%
How much plasma is included in a unit of packed red cells that is preserved with CPDA? - Correct Answer
In CPDA units: 50 mL
What is the frequency of the k antigen in the donor population? - Correct Answer - 98.8%
- -k antibody, only 0.2% of
donors will be compatible with this patient
,Are anti-M antibodies IgG or IgM? Are they normally clinically significant? - Correct Answer - Anti-M
tends to be IgG
- Even though they are IgG, they are most often cold reactive antibodies and are therefore clinically
insignificant
What is the Cobalt (Co) antigen? - Correct Answer It is found on the plasma membrane of red blood
cells and renal tubular epithelial cells. It is on a protein called aquaporin-1 (AQP1 gene product), which is
responsible for water homeostasis and urine concentration.
How frequent is the Co(a) antigen in the donor population? - Correct Answer - Found in 99.8% of donors
- Thus finding Co(b) or Co-null blood is very difficult
Are anti-Co(a) antibodies IgG or IgM? Are they normally clinically significant? - Correct Answer - Usually
IgG antibodies
- Can cause hemolytic transfusion reaction and HDFN
A post-transfusion blood sample has a positive DAT. What is the next appropriate procedure? - Correct
Answer An elution test should be performed to find the antibody specificity.
Possible reasons for a panreactive antibody on DAT. - Correct Answer - Warm autoantibody
- An antibody to a high incidence antigen
Is a DAT-positive donor unit likely to have clinically significant antibodies? - Correct Answer No, because
the antibodies bound to the donor red cells will stay bound in vivo in the recipient.
The reactivity of blood group A is confirmed by detecting the presence of which immunodominant sugar
molecule? - Correct Answer The A gene codes for production of N-acetylgalactosamine transferase, an
enzyme which binds N-acetylgalactosamine (GalNAc) to the H structure (L-fucose).
A mnemonic for remembering that the carbohydrate in blood group A is N-acetylgalactosamine. -
Correct Answer In my opinion, the best way to recognize the full sugar name is to remember the
abbreviation. GalNAc would likely point you towards something containing a "...gal..." in the answer. -
bbguy.org
,Why do individuals with the Bombay phenotype (O(h)) lack alloanti-O antibodies? - Correct Answer "O,
please remember, is not an antigen, it's the lack of A and B antigens, so anti-O is not a legitimate
antibody." -bbguy.org
Which cells agglutinate most strongly with Ulex europaeus lectin? - Correct Answer This particular
lectin, when tested against human red cells, closely parallels the reactivity we'd expect to see if we used
actual anti-H. The main blood groups agglutinate with the following relative strength with anti-H or Ulex
groups, but also have a molecular structure that leaves fucose very accessible to anti-H. As a result,
these cells agglutinate very strongly with Ulex.
What are some characteristics of naturally occurring (non-alloimmune) antibodies that distinguishes
them from alloimmune (transfusion-related) antibodies? - Correct Answer In short, naturally occurring
antibodies are generally of the IgM class, not able to cross the placenta, enhanced in reactivity by
incubation at 4C, and cause direct agglutination at room temperature.
ABOMNILS are red cell stimulated (not naturally occurring)
What ABH substances would be found in the saliva of a group B secretor? - Correct Answer H and B. The
secretor status of an individual (genotype SeSe or Sese) determines the formation of H antigen in
secretions, which in turn creates opportunity for A and B antigen formation, if either (or both) gene is
inherited
Can an individual of a secretor phenotype (genotype of SeSe or Sese) have O antigen in their secretions?
- Correct Answer No. There is no such thing as O antigen!
The ABO system is the most important blood group system in transfusion safety. Why? - Correct Answer
ABO is the only blood group system in which reciprocal antibodies are normally produced for the
antigens an individual lacks AND the ABO antibodies are capable of causing rapid, intravascular
hemolysis.
An ABO discrepancy between forward and reverse grouping owing to weak-reacting or missing
antibodies could be BEST explained by _____. - Correct Answer Patients with extreme ages (the very old
or the very young). In the very old and very young, the natural expression of isoagglutinins can either be
depressed or delayed, respectively
, What could be the cause of a missing red cell (forward) reaction type of ABO incompatibility? - Correct
Answer Group A subgroups often lead to missing red cell (forward) reactions
What could be the cause of an ABO discrepancy that results in an extra red cell (forward typing)
reaction? - Correct Answer Acquired B phenomenon results in extra red cell reactions
A blood donor has the genotype hh, AB. What is his apparent red cell phenotype during routine forward
and reverse group typing? - Correct Answer Type O. Without either the HH or Hh genotype, and the
resulting "H Structure," the A and B antigens inherited as part of the AB genotype are unable to attach
to the RBC membrane type 2 chains. Such an individual's red cells would appear as group O,
phenotypically.
-
Correct Answer About 80%
- Correct Answer Dolichos biflorus
duce naturally occurring (ie, immune) anti-
clinical significance of these antibodies? - Correct Answer Anti-
insignificant
Which genes codes for production of the same basic antigen as the H gene? - Correct Answer Secretor
(Se) gene
Color of anti-B reagent antibody - Correct Answer Yellow
Color of anti-A reagent anti-body - Correct Answer Blue
Which reagent antibody is in this bottle? - Correct Answer Anti-B
Which reagent antibody is in this bottle? - Correct Answer Anti-A
