Blood Bank ABO/Rh

What are the three causes of weak D antigen?

- Most Common: Weak expression cDe (R0) and more prevalent in the black population in America - Positional effect: C trans effect on D most common - Mosaic/Partial D (qualitative)

A negative ABO/Rh result using solid phase tubes using patient plasma and indicator cells will have: a cell button in the bottom of the tube b cells dispersed thru out the tube

a cell button in the bottom of the tube

An AHG crossmatch is always performed if a patient has:

a current or historical clinically significant crossmatch

Reverse typing tests ________________a__________________ serum and _____________b__________________ red cells

a patient/donor b reagent

Forward typing tests __________a___________ serum and _________b_____________ red cells.

a reagent b patient/donor

A positive (4+) gel method ABO/Rh result will have: a red cells at the top of the gel tube b red cells thru out the gel tube c red cells at the bottom of the gel tube d red cells at the top and bottom of the tube

a red cells at the top of the gel tube

Blood type O individuals have what antibodies?

anti-A anti-B anti-A,B which is IgG and may cross the placenta

What reagent is used to test for Bombay (hh) Phenotype in an individual who tests like O: Anti-A Reagent Sera = 0 Anti-B Reagent Sera = 0 A1 Red Cells = 4+ B Red Cells = 4+

anti-H Ulex europaeus plant lectin

What antibodies are most often clinically insignificant and show the strongest reactivity in the IS phase and lessened in the LISS/37*C phase?

anti-Lewis anti-I anti-P anti-M anti-N

What reagent is used to test A1 Phenotype red cells? a Ulex europaeus b Dolichos biflorus c Vicia cracca d Vicia graminea e Griffonia simplicifolia

b Dolichos biflorus

the ABO genes are located on what chromosome? a X b 21 c 9 d 12

c 9

All of the following are true regarding formation of the ABH antigens except: a H gene inheritance is independent of ABO gene inheritance b A B H antigens are formed from the same precursor material c A type I structure refers to a beta 1-2 linkage d a type II structure refers to a beta 1-4 linkage

c A type I structure refers to a beta 1-2 linkage (they are beta 1-3)

If a patient has a weak positive reaction for screening cells 1, 2 & 3 with a negative auto control (HTLA: high titer/low avidity), the antibody may be against what type of antigens? a low frequency b medium frequency c high frequency

c high frequency

A positive (3+) tube method ABO/Rh result will have: a hemolysis b small aggregates and turbid background c large aggregates and clear background d one cell button

c large aggregates and clear background

What is the most important criterion in selecting screening cells?

cells should be homozygous for one or more clinically significant antibodies Note: D and Kell (K) only require heterozygous because K are most often found with Cellano/k

Where is the H locus found? a X b 9 c 21 d 19

chromosome 19

What gene(s) will an ABH secretor have? a SeSe b Sese c sese d both a and b

d both a and b

What is DAT?

direct antigen testing of patient's RBCs

What ABO blood type can donate to a patient who has Bombay Phenotype? a A-neg b B-neg c O-neg d AB-neg e hh

e hh

What blood type has the greatest H antigen concentration? What blood type has the lowest H antigen concentration?

greatest : O least: A1B O > A2 > B > A2B > A1 > A1B

IS or electronic crossmatches can be the only crossmatch performed if the patient has what two requirements met:

has no historical history of clinically significant antibodies has a negative antibody screen

What is IAT?

indirect antibody screen testing patient's serum/plasma for antibodies

Why does rouleaux disappear at the AHG phase of testing?

this phase occurs after washing the red cells free of serum/plasma

The H gene codes for what enzyme and what does it do?

transferase, which transfers fucose to the terminal galactose residue on the red cell precursor molecule

A patient plasma reacts with the following reagent cells and has the following reactions. What is the patient's blood type & why: Forward Type: anti-A = 0 anti-B = 0 anti A1B = 0 anti-A1 = 0 Back Typing: A1 cells = 4+ A2 cells = 4+ B cells = 4+ O cells = 4+ Auto Ctl = 0 Cord Blood = 4+

Bombay with anti-H They don't make the precursor H-antigen that A or B antigens bind to. They have antibodies to all A, B & H antigens.

What red cells can a person with type AB receive?

Universal acceptor: A, B, AB or O

What is the main function of an IS crossmatch?

To detect ABO incompatibility

Most current anti-D reagents will detect weak D expression. T/F

True

If parent have AO & BO genotypes, what percentage of offspring will likely have type O blood?

25% or 1/4

Rule in (inclusion)

3 positive reactions in cells that react with patient plasma are required for that antibody to be studied further (antigen testing of patient red cells)

What is the prevalence of E antigen in the Caucasian population?

30%

What is the prevalence of AB antigen in the Caucasian population?

4%

What is the prevalence of A antigen in the Caucasian population?

43%

How many ABO genotypes are there?

6 AA AO BB BO AB OO

What is the prevalence of C antigen in the Caucasian population?

68%

How many times must cord blood be washed?

6x

What is the prevalence of c antigen in the Caucasian population?

80%

What is the prevalence of D antigen in the Caucasian population?

85%

What is the prevalence of K or B antigen in the Caucasian population?

9%

What is the patient's blood type: Forward: anti-A = + anti-B = 0 Reverse: A cells = 0 B cells = +

A

What are the four ABO phenotypes?

A B AB O

H/h locus codes for the production of ________________A_____________________ that facilitates the placement of ________B____________ onto the RBC membrane so that A or B sugars may be placed.

A L-fucosyl-transferase (a glycosyltransferase) B L-fucose

Which of the following is considered to be a high prevalence antigen? A. Vel B. Jsa C. s D. K

A. Vel anti-Vel: - reacts at 37*C - IgM - Causes HTR (not HDFN) Sd^a is also a high prevalence antigen, but acts at the AHG phase

A drug-induced immune hemolytic anemia caused by a drug-independent antibody would have which of the following results? A. positive DAT with IgG; positive antibody screen B. positive DAT with IgG; negative eluate C. positive DAT with C3d; negative antibody screen D. negative DAT; positive antibody screen

A. positive DAT with IgG; positive antibody screen The antibody detected in drug-independent immune hemolytic anemia is indistinguishable from warm autoantibodies. The DAT is positive with IgG, the eluate and serum react with all cells tested. Drugs that are known to cause this are methyldopa and fludarabine.

What two subgroups of blood type A do 99% of the population have?

A1 & A2

A patient plasma reacts with the following reagent cells and has the following reactions. What is the patient's blood type & why: Forward Type: anti-A = 4+ anti-B = 0 anti A1B = 4+ anti-A1 = 0 Back Typing: A1 cells = 1+ A2 cells = 0 B cells = 4+ O cells = 0 Auto Ctl = 0 Cord Blood = 0

A2 with anti-A1 An A (subtype) because patient RBCs reacted strongly with reagent antibodies for A + A1B Not A1 because patient plasma reacted with A1 reagent cells = anti-A1

What group A subtype is more likely to be classified at type O, but are generally not clinically significant unless donated to a type O individual? A1 A2 A3 A4

A3

What blood type is a universal plasma donor?

AB

What is the patient's blood type: Forward: anti-A = + anti-B = + Reverse: A cells = 0 B cells = 0

AB

What antibody group reacts best at IS "cold antibodies" temperatures?

ABO

Clinically significant antibodies

ABO, Rh, Kell, Duffy, Kidd, SsU React at 37*C Cause agglutination at AHG phase

How is patient sensitization of Rh negative blood products prevented?

Dosing with Rhogam or WinRho which are concentrated anti-D / Rh immune globulin

What is the patient's blood type: Forward: anti-A = 0 anti-B = + Reverse: A cells = + B cells = 0

B

Inheritance of the rare Mk gene results in the deletion of both GYPA and GYPB. Which of the following blood group antigens is not expressed on red cells in the presence of a Mk gene? A. Kx B. Ena C. f D. G

B. Ena The rare Mk gene leads to a deletion of the GYPA and GYPB genes. These red cells have a normal morphology and phenotype as M-N-S-s-U-; En(a-); Wr(a-b-). MkMk is a null phenotype in the MNS system and is associated with reduced RBC sialic acid and increased glycosylation of Band 4.1 and Band 3.

The preferred replacement fluid to maintain normal oncotic pressure and intravascular fluid levels for patients who have therapeutic plasma exchange (TPE) for thrombotic thrombocytopenic purpura is: A. IVIg B. plasma C. crystalloid solutions D. isotonic saline

B. plasma For patients with thrombotic thrombocytopenic purpura (TTP), therapeutic plasma exchange TPE using plasma is accepted as first-line therapy and is generally performed daily. The use of plasma prevents depletion of coagulation factors.

The observed phenotypes in a particular population are: What is the gene frequency of Jka in this population? Phenotype.....# of People Jk(a+b-)............122 Jk(a+b+)............194 Jk(a-b+)............84 A. 0.31 B. 0.45 C. 0.55 D. 0.60

C. 0.55 Use the Hardy-Weinberg equation: p2 + 2pq + q2 = 1.0. In this example, p2 is the homozygous population, Jk(a+b-). The square root of p2 = p, which is the gene frequency of Jka in this population. Out of 400 people, 122, or 30% are homozygous. The square root of 0.30 = is 0.55.

Which of the following phenotypes is the result of homozygous inheritance of the corresponding genes? A. Le(a+b-) B. M+N+ C. Fy(a-b+) D. Jk(a+b+)

C. Fy(a-b+)

Based on the results below, what is the next step in determination of the patient's ABO/Rh type? anti-A 4+ anti-B 4+ anti-D 4+ A1 Cells 0 B Cells 0 A. interpret at AB, D-positive B. interpret at AsubB, D-positive C. repeat ABO red cell typing and include a control D. add room temperature incubation with ABO red cell typing

C. repeat ABO red cell typing and include a control to verify the results are correct

Rosenfeld to Fisher-Race nomenclature conversion for Rh groupings is:

D C E c e d 1 2 3 4 5 6

What sugar is transferred to the H-antigen in a person with B gene(s)?

D-galactose

A unit of Fresh Frozen Plasma was inadvertently thawed and then immediately refrigerated at 4°C on Monday morning. On Tuesday evening this unit may still be transfused as a replacement for: A. all coagulation factors B. Factor V C. Factor VIII D. Factor IX

D. Factor IX Factors V and VIII would be decreased but IX would not be decreased. Thawed FFP should be used within 24 hours. Refrigerated plasma (never frozen) is good for 5 days.

A patient's serum sample was reactive with all cells except the autocontrol when tested by PEG-AHG. The patient's phenotype was confirmed as: C-E+c+e+; K-k+, Kp(a-b+),Js(a-b+); Fy(a-b+); Jk(a-b-); M+N+S+s+. Phenotypically similar cells were tested and found to be nonreactive. In what population of donors are we most likely to find a compatible donor for this patient? A. African B. Middle Eastern C. South American D. Tahitian

D. Tahitian As high as 1 in 400 people of Polynesian ethnicity have a silent gene at the JK locus, leading to the Jk(a-b-) phenotype.

Which of the following Rh antigens has the highest frequency in Caucasians? A. D B. E C. c D. e

D. e at 98% D = 85% c = 80% E = 30%

Match: D POS D NEG With: DD Dd dd

DD = POS Dd = POS dd = NEG

Forward typing is considered a/an _________________ antiglobulin test / ______ that tests for _________ or _______ using polyspecific reagent.

Direct / DAT IgG or C'

What are the basic steps of the IS phase of testing?

First step of testing diluted red cells and patient serum or plasma are added to a test tube at room temperature immediately centrifuged ("spun") examined visually for agglutination. A positive immediate spin reaction suggests ABO incompatibility between serum and RBCs or the presence of a "cold" or room-temperature reactive antibody.

The Rh nomenclature which uses the letters DCE is found in which of the following genetic models:

Fisher-Race

What type of typing does cord blood go through?

Forward typing only, there are no antibodies to test yet.

AHG phase is helpful in detecting Ig____ antibodies attached to red cell antigen.

IgG

Rh antibodies are primarily of which immunoglobulin class?

IgG1 or IgG3

What immunoglobulins listed can NOT bind complement: IgG1 IgG2 IgG3 IgG4 IgM

IgG4

What immunoglobulins listed can NOT cross the placenta: IgG1 IgG2 IgG3 IgG4 IgM

IgM

Antibodies that react at IS (room temp) are usually Ig__a___ and clinically insignificant / significant, while antibodies that react in the LISS or AHG phases are more likely to be Ig___b__ and clinically insignificant / significant.

IgM & Insignificant IgG & Significant

Reverse typing is considered a/an ______________________antiglobulin test or _______.

Indirect / IAT

What are the basic steps of the AHG phase of testing?

Last step of testing incubation at 37*C x 10-30 min followed by a washing 4x step to remove free antibodies. Add anti-human globulin ('AHG') to the Serum + Reagent RBC mix Centrifuge the tube Examine immediately to see if the AHG agglutinates red cells that were coated with antibody (usually IgG) in earlier steps. This process is really just an indirect antiglobulin (Coombs) test. Most clinically significant antibodies will react at the AHG phase (and some may react at 37oC as well).

Most ABO antibodies are Ig_____ and cannot cross the placenta

M

If a DAT test is positive, what reagents are used separately in the next part of the testing methodology?

Monospecific IgG and C' (eg C3d)

The most & least common blood types across the general population are:

Most O Lease AB

What sugar is transferred to the H-antigen in a person with A gene(s)?

N-acetylgalactosamine

Does an type O person have anti-H in their plasma/serum?

No, only Bombay phenotype does

What blood type is a universal Red Cell donor?

O

What is the patient's blood type: Forward: anti-A = 0 anti-B = 0 Reverse: A cells = + B cells = +

O

What red cells can a person with type O blood receive?

O

A patient is group O, Rh-negative with anti-D and anti-K in her serum. What percentage of the general Caucasian donor population would be compatible with this patient? A. 0.5 B. 2.0 C. 3.0 D. 6.0

O group neg = 45% anti-D pos = 85% anti-K pos = 9% [(1.-.85) x (1.-.09) x .45] x 100= (.15 x .91 x .45) x 100 = .06 x 100 = 6%

Screening cells #1 & 2 are always ABO/Rh type _________ and #3 is ABO/Rh type _____________

O pos O neg

A patient with phenotype DCE/dce would be RH POS/NEG? Weiner genotype would be?

POS Rzr

What antibodies react at 37*C "warm antibodies"?

Rh

Positional Cis effect of Rh gene expression

Rh gene affects the expression of another Rh gene on the same chromosome. eg D gene produces a weaker E gene on same chromosome (cDE is weaker then cdE)

Positional Trans effect on Rh gene expression

Rh gene effects the expression of a gene on another Rh gene on a different chromosome eg CDe/Cde => weakens D antigen

What is the most prevalent genotype for Rh in Fisher-Race and Weiner nomenclature?

RhD+ POS Genotype: D+C+E-/c+e+ F-R: DCe/dce W: R1r 2nd & 3rd also have DC

What further testing is required on all Rh negative donor blood, but not of Rh negative patients?

Testing for weak D for either poorly expressed or missing portions of D antigens.

A patient has the following anti-D reactions, what is their Rh type? IS: 0 37*C: 0 AHG: +

Weak D

An adult O-pos blood type trauma patient needs platelets and there are no type-specific platelets available. Can type A, B or AB platelets be transfused? Why?

Yes, because platelets have very weak expression of ABO antigens and are not lysed

A male trauma patient that is Rh negative can/cannot receive Rh positive blood? Why?

Yes, while highly immunogenic, the likelihood that the person has already received Rh positive blood products is low (stimulating prior IgG production), IgG takes 2-3 weeks to appear, and anti-D IgG antibodies produced will not cause HDFN in the future.

A person with a combination of the genes: HH or Hh BB or BO Sese will secrete: a B and H b B only c H only d None

a B and H

What ABO typing(s) are performed on cord blood and infants < 3 months of age? a Forward only b Reverse only c Forward & Reverse d None

a Forward only because antibodies haven't developed yet

ABH substances found in secretions or non-RBC tissues are found on Type ___a____ structures while those found on RBCs are Type __b__ structures:

a I (1) b II (2)

Check/Sensitized cells are coated with ____a____ and are used to determine the validity of testing at the ____b______ phase and check for what errors?

a IgG b AHG That the cells were not washed properly and the IgG was added.