Blood Bank review exam 2

What are weak D donor cells labeled as?

Rh positive

Who should receive weak D donor cells?

Only Rh positive patients

If a recipient is B, weak D+ what type should they be transfused with?

B+ or O+

Who must have a weak D test performed if the D is negative?

Blood donors and pregnant women

What must be run if a patient is AB positive and why?

D control; to rule out polyagglutination

When should polyagglutination be considered?

Positive reaction using monoclonal/polyclonal D antisera

What does weak D mean?

Fewer antigenic sites available for the D antigen on patient red cells

What does partial D mean?

D antigen is present but lacks part of the molecular structure

What is another term for partial D?

D mosaic

When should a D mosaic or partial D be suspected?

When a D+ patient makes anti-D that is nonreactive with their own cells

Which antibody is likely to be seen with partial D?

Anti-D

Could a B weak D+ develop anti-D if the person is a mosaic?

Could but it is rare

Why would your Rh control be positive at IS?

Something is coating patient cells

Why would your Rh control be positive only at AHG?

Positive DAT

What must you do if your Rh control and DAT are positive?

Glycine EDTA treatment

What does the glycine EDTA treatment do?

Dissociates whatever is coating patient cells

What does a positive Rh control indicate?

Invalidates phenotype

If high protein anti-D is used and both the weak D and control are positive, what does this indicate?

Invalid Rh; repeat with monoclonal or mono/poly blend

What should be done if a weak D positive control cannot be resolved?

Give Rh negative blood

What is an IAT?

Detecting aby-agn complex **in vitro**

What is the purpose of IAT?

Identify unexpected IgG antibodies in patient plasma

What does dosage indicate?

Homozygous or heterozygous reaction

Which dosage has a stronger reaction?

Homozygous

What might cause variation in reaction strength in the antibody screen?

Dosage, multiple antibodies, poor technique

What temperatures of antibodies are clinically significant?

37C or AHG

Which phase do Rh antibodies react at?

37 and stronger at AHG

Which phase do Kell, Kidd, and Duffy families react at?

AHG

Which phase do M/N antibodies react at?

IS

Which phase do S/s antibodies react at?

AHG

Lea-b- and Fya-b- phenotypes are found mostly is what patient demographic?

African american

What is the racial/ethnic background of someone who has Le^a, Le^b, and Fy^a antibodies?

Black

What are the most commonly identified clinically significant antibodies?

Rh, Kell, Duffy, & Kidd

Why are Rh, Kell, Duffy, & Kidd antibodies considered clinically significant?

\-IgG class \n -Capable of causing HDN \n -Capable of causing transfusion reaction

What is the most antigenic antibody?

D

What is the next most antigenic antibody after D?

Kell

Which antibody family is associated with malaria?

Duffy

Which antibody family is notorious for causing delayed hemolytic transfusion reaction?

Kidd

Why does the Kidd antibody family often cause DHTR?

Titer drops to undetectable levels

Which antibody family has the ability to react at RT/37/AHG?

Lewis

Which antibody can cause hemolysis in IAT at RT?

Lea

Is the Lewis family clinically significant? Which class are they?

No; IgM

Why are Lewis antibodies not considered clinically significant?

1. Cannot cross the placenta


1. Newborns have the genotype Le^a = Le^b =

When is it common to identify Lewis antibodies? Why?

During pregnancy; antigen expression decreases during pregnancy

Cold autoantibodies will cause false positive or negative results for reverse typing if the antibody titer is high?

Positive

How can a typing discrepancy due to a cold antibody be resolved?

Warm patient plasma to 37C and repeat

What are the cold reacting antibodies?

Anti-I, -i, -P1

What is the most common cold reacting autoantibody of IgM class?

Anti-I

Which antibody is formed following mycoplasma pneumoniae infection?

Anti-I

Anti-I reacts with which cells?

O cells, A2 cells, patient's cells, does not react with cord cells

Which antibody is formed following infectious mono?

Anti-i

When does a cold autoantibody become clinically significant?

Reactions through AHG phase

Production of antigens in tissue cells and subsequent absorption by RBCs is a characteristic of this blood group?

Lewis

If the IAT is positive you must:

\-Perform an antibody panel \n -Phenotype the patient's cells to look for lack of antigen \n -Make sure the donor is antigen negative

What is ZAPP?

Combination of papain and DTT, destroys Kell antigen in addition to those destroyed by enzyme

Which antibodies can be treated by neutralization?

Lewis family & P1

Which antibodies are enhanced with enzyme treatment?

Rh, Lewis, and Kidd

Which antibodies are destroyed with enzyme treatment?

Duffy & MNSs

What is used to resolve multiple antibodies?

Papain/ficin, reaction strengths and reaction temperature, neutralization

When is rouleaux commonly seen?

Multiple myeloma

What is rouleaux caused by?

Imbalance of serum proteins

What is the "Rule of 3"?

Must have 3 positives and 3 negatives to be 95% accurate

What does an elution do?

Removes antibody from the cell membrane in vivo so it can be identified

What are some different types of elutions?

Heat treatment, acid treatment, Lui freeze

Lui Freeze-Thaw elution method is used for what?

Investigate HDN

What enzymes can be used with enzyme treatment?

Papain or Ficin

How does enzyme treatment work?

Interrupts the sialic acid among the cell membrane and destroys the antigen sites that extend from the cell membrane (M/N, S/s, Duffy)

What does enzyme treatment treat?

Commercial cells

What is the inactivation of the antibody by binding it with a soluble antigen?

Neutralization

What does neutralization treat?

Patient plasma

What is a common enhancement media used in blood bank?

LISS (Low Ionic Strength Solution)

What reagent helps further break down the zeta potential around the cells allowing for increased uptake of antibody on the cell? (Helps enhance agglutination reaction)

LISS

Rh nomenclature

R = D
r = no D (d)
0 or = ce
1 or ' = Ce
2 or " = cE
z or y = both CE

What is Fisher-Race for R1?

DCe

What is Fisher-Race for R2?

DcE

What is Fisher-Race for Rz?

DCE

What is Fisher-Race for R0?

Dce

What is Fisher-Race for r'?

dCe

What is Fisher-Race for r"?

dcE

What is Fisher-Race for ry?

dCE

What is Fisher-Race for r?

dce

When what antigen is present, it weakens the expression of the D antigen?

C antigen

Which antigen expression has the greatest antigenic D expression?

R2R2

What is the term for the majority of the population is **positive** for an antigen?

Public antigen; Lu^b most people have this antigen

What is term for the majority of the population is **negative** for an antigen? What is an example?

Private antigen; Lu^a, most people lack this antigen

Which type of antigen will blood bank have a harder time finding compatible cells for? What is an example?

Antibody to public antigen; anti-k

What problem do we run into if our patient has an antibody to a private antigen?

Private antigens are not usually included on the IAT

How are private antibodies usually detected if not found during the IAT?

During crossmatch, units will not be compatible

Which antigen is also with the ABO antigens at birth and exists as an oligosaccharide coming of the RBC membrane? What does it change into at around 6 months of age?

i antigen; I antigen

Which blood group has the greatest amount of H substance?

O

Which blood group can build anti-H? Why?

A1B most likely; has the fewest antigen sites

What makes holes in the cell membrane?

Complement

What detects attachment in vivo?

DAT

Which antibody class can cause intravascular hemolysis? What is an example?

IgM; ABO antibodies

Which antibody class can cause extravascular hemolysis?

IgG

How do we describe when an antibody is developed in response to an antigen?

Immunized to the antigen

What is used to detect A1?

Lectin

What are check cells coated with?

O positive cells coated with anti-D which is an IgG antibody

What blood type are screening cells?

O

What reagent detects complement in vivo?

Polyspecific AHG or monospecific C3b, C3d

Polyspecific AHG detects which complement component?

C3b, C3d