Abigail's Generalist MLS Deck

Note: Does not contain microbiology

What is the liquid remaining after blood clots that contains antibodies?

Serum

The binding strength of a single antibody and antigen is known as…

Affinity

Why does centrifugation enhance agglutination?

Centrifugation reduces the zeta potential, which is the negative-charge repulsion between the cells.

What is the ideal pH for agglutination reactions?

6.5–7.5

Which antibody requires the use of potentiators to visualize reactions?

IgG

What is anti-IgG mainly specific to?

Gamma heavy chain

Why is anti-complement used rather than anti-IgM?

It is an “indirect” way of detecting IgM due to its ability to bind complement.

A lab tech washed a sample for a DAT only one time. How should the negative result be interpreted?

False negative due to debris

Which of the following is not a potential condition for a positive anti-C3 with 2–4+ reaction?

HDFN

Which of the following is not a potential condition for a positive anti-IgG with a 2-4+ reaction?

CAIHA

What are the three genes that affect ABO inheritance?

ABO, Hh, and Se

What does the H antigen elicit production of?

alpha-2-L-fucosyl transferase

What kind of chain does L-fucose transfer to?

Type 2

What blood type does this image represent?

Blood type A

What blood type does this image represent?

Blood type B

In ABO blood typing, the reagents are predominantly composed of what?

Monoclonal IgM

What is the order of blood type strength of Ulex europaeus agglutination from strongest to weakest?

O>A2>B>A2B>A1>A1B

What blood group do Bombay and para-Bombay individuals belong to?

O blood group

An elderly woman presents with a forward type of O but does not react to A₁ cells or B cells, what discrepancy group is most likely?

Group I

GalNAc cleavage due to enteric bacteria deacetylase, creating a molecule more antigenically similar to GAL is known as…

Acquired B syndrome

How should suspected group III typing discrepancies be resolved?

Washing six times and/or saline replacement

What antigen must be present for the expression of RhD and/or RhCE?

RhAG

Genes that code for D and C also code for which antigen?

G

Anti-G activity cannot be separated from what two antibodies?

Anti-D and anti-C

What antigen is also expressed if a person is ce?

f

What is the order of immunogenicity of the Rh group antigens?

D > c > E > C > e

Is a transfusion reaction primarily intravascular or extravascular hemolysis?

Extravascular

R1R1 people with anti-E most always also make what?

Anti-c

Anti-C is rare but usually accompanies what?

Anti-D

After the addition of IgG-coated RBCs (check cells) to a negative AHG reaction during an antibody screen, a negative result is observed.

Which of the following is a correct interpretation based on these findings?

Unable to be interpreted

An in vivo phenomenon associated with positive DAT is:

Maternal antibody coating fetal RBCs

What are the possible ABO phenotypes of the offspring from the mating of a group A to a group B individual?

O, A, B, AB

An example of a technical error that can result in an ABO discrepancy is:

Cell suspension that is too heavy

You are working on a specimen in the laboratory that you believe to be a Bombay phenotype. Which of the following reactions would you expect to see?

Patient's cells + Ulex europaeus = no agglutination

Biochemically speaking, what type of molecules are Rh antigens?

Protein

Cells carrying a weak D antigen require the use of what test to demonstrate its presence?

IAT

How are Rh antigens inherited?

Codominant alleles

If a patient who is R1R1 is transfused with RBCs that are R⁰r, which antibody is he most likely to produce?

Anti-c

Which Rh phenotype has the strongest expression of D?

Dce/Dce

What does hr' refer to in the Weiner nomenclature?

c

The antihuman globulin (AHG) test was discovered in 1945 by whom?

Coombs

What is the biochemical structure of secreted A, B, and H substances?

Glycoprotein

Which ABO group’s reaction will be the weakest with anti-H lectin?

A1B

What percentage of the type A population is A2?

20

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

What is the action of PEG?

Removes water molecules, thereby concentrating antibody

Which of the following is most immunogenic?

D

Which of the following is least immunogenic?

e

What is the source of anti-A1 lectin?

Dolichos biflorus

Why is incubation omitted in the direct AHG test?

In vivo antigen antibody complex is already formed

What do "check cells" contain?

D+ red cells coated in anti-D

The Rh antibody agglutinates what percentage of RBCs?

85

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.

How is polyclonal antiglobulin serum made?

Human serum is injected into rabbits, and an immune response triggers the production of an antibody.

What substances are found in a group A secretor?

AH

Most clinically significant antibodies belong to which antibody class?

IgG1 and IgG3

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?

Cannot be determined due to positive DAT

What does Rh genotype refer to?

Rh genes inherited from both parents

Why is determination of Rh status crucial for obstetric patients?

All Rh-negative mothers are possible candidates for Rh immune globulin.

What immunodominant sugar is responsible for B specificity?

D-galactose

What does the "R" represent in Rh-Hr terminology?

Presence of D

Why can anti-H sometimes be found in an A1B individual?

The specific immunodominant sugar blocks presence of H antigen.

Why is reverse grouping not performed on cord blood specimens?

Antibodies are generally not present at birth.

A group O person with warm autoimmune hemolytic anemia may demonstrate weak reactions in the forward grouping due to:

Antibody coating

All of the following statements regarding the AHG test are true except:

Incubation time with LISS should be a minimum of 30 minutes.

Which of the following criteria is used to classify the B subgroups?

All of the above

All of the following is true regarding formation of the ABH antigens except:

A type 1 structure refers to a beta 1-2 linkage.

Why are check cells added to all negative reactions in the AHG test?

To ensure AHG was not neutralized by free globulin molecules

All of the following conditions may produce a positive DAT except:

Lymphoma

Where is the Rh antigen located relative to the red blood cell membrane?

Integrally

Anti-A from a group B individual is primarily what class of immunoglobulin?

IgM

An advantage of polyclonal anti-IgG over monoclonal anti-IgG is:

Polyclonal anti-IgG will recognize IgG variants.

All of the following may cause a false-negative reaction in Rh typing except:

Rouleaux

Which of the following is not characteristic of antibodies within the ABO system?

ABO antibodies do not activate complement.

Which gene combination is expressed in the greatest frequency in the black population?

Dce

What substances would be found in the saliva of a group B secretor who also inherited Lele genes?

H, B, Lea, Leb

An MLS has decided to test an enzyme-treated panel of RBCs against a patient's serum. Which of the following antibody pairs could be separated using this technique?

Anti-Fya and anti-Jka

In what way do the Lewis antigens change during pregnancy?

Lea and Leb both decrease

An antibody demonstrates weak reactivity at the AHG phase when the tube method is used with no enhancement reagent and monospecific AHG reagent.

When repeating the test, which of the following actions may increase the strength of the positive reactions?

Adding an enhancement, such as LISS or PEG

A type 1 chain has:

The terminal galactose in a 1-3 linkage to subterminal n-acetylglucosamine

A patient with an M. pneumoniae infection will most likely develop a cold autoantibody with specificity to which antigen?

I

Anti-U will not react with which of the following RBCs?

M+N-S-s-

Which of the following antibodies is not IgM?

Anti-Jka

An antibody demonstrates weak reactivity at the AHG phase when the tube method is used with no enhancement reagent and monospecific AHG reagent. When repeating the test, which of the following actions may increase the strength of the positive reactions?

Adding an enhancement, such as LISS or PEG

Red blood cells treated with proteolytic enzymes will demonstrate enhanced reactivity with:

Anti-D

A request for 8 units of RBCs was received for patient L.F. The patient has a negative antibody screen, but 1 of the 8 units was 3+ incompatible at the AHG phase.

Which of the following antibodies may be the cause?

Anti-Kpa

Which autoantibody specificity is found in patients with PCH?

Anti-P

The American College of Surgeons recommends transfusion of RBCs, thawed plasma, and platelets in what ratio for a massive transfusion?

1 unit of RBCs to 1 unit thawed plasma to 1 unit of platelets

A patient with sickle cell disease is B positive with a positive antibody screen. The antibody identified is anti-D, and the autocontrol is negative. What is the possible explanation?

Patient possesses the partial D phenotype.

A patient's antibody screen was positive and anti-c was identified. AHG crossmatches were performed with c-negative units and 1 out of the 6 units were found to be incompatible.

All of the following should be done to investigate this incompatible unit, exceot:

Give O negative RBCs

A patient with sickle cell disease is B positive with a positive antibody screen. The antibody identified is anti-D, and the autocontrol is negative. What is the possible explanation?

Patient possesses the partial D phenotype

Which antibody specificity is not required in antibody detection tests?

Cw

How many days must a pretransfusion specimen and donor unit be retained post-transfusion?

7 days

An individual from Bombay who has inherited the Le gene will have a phenotype of…

Le(a-b-)

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

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

How is Leb substance formed?

L-fucose is added to subterminal N-acetylglucosamine of type 1 H substance.

Which of the following is not involved in the Kell blood group system?

Jka

What is the most common Kidd phenotype in the black population?

Jk(a+b-)

Why is dosage inconsistent in the Duffy blood group?

The genotype could be inherited as FyaFya or FyaFy for Fy(a+b-) red blood cells.