lecture questions exam 2

Question 1

A patient’s serum reacts with 2 of 3 antibody screening cells at the AHG phase of testing. 8 of 10 crossmatched units were incompatible at AHG. All reactions were markedly enhanced with enzymes. Which antibody is likely reacting
- anti-M
- anti-E
- anti-little c
- anti - Fya

Answer 1

anti-little c
- little c higher incidence (8/10) than E (2/10)
- duffy and MNS systems are destroyed by enzymes

Question 2

which characteristics are true of all 3 of the following antibodies: anti-fya, anti-jka, anti-k
- may show dosage, may cause severe hemolytic transfusion reactions
- detected at IAT phase and may cause hemolytic disease of the newborn and transfusion reactions
- requires IAT techniques for detection usually not responsible for HDN

Answer 2

detected at IAT phase and may cause hemolytic disease of the newborn and transfusion reactions
- Fya, Jka and anti-k are IgG so need IAT and may cross placenta

Question 3

an auto control gives a mixed field result, is this a valid test result
- yes, the result shows that the patient has an autoantibody
- yes the patient has probably recently been transfused
- no, the panel cells cannot give a mixed-field result, something is wrong with the test system
- no, the control has failed, the test needs to be repeated

Answer 3

yes the patient has probably recently been transfused
- auto control = self cells against self plasma
- mixed field indicates two populations of cells reacting w/in auto control
- a true auto-antibody would have a stronger reaction

Question 4

which pair is NOT a set of antithetical antigens
- Jsa/Jkb
- E/e
- Fya/Fyb
- M/N

Answer 4

Jsa/Jkb
- MNS system vs kidd system

Question 5

A donor unit caused a delayed transfusion reaction where a patient developed an anti-Jsa. Given expected antigen frequencies, what is the likely population the donor is from?
- caucasian
- asian
- black
- hispanic

Answer 5

black
- Jsa is 20% more frequent in black populations than others (0 vs 20)

Question 6

which set of antigens are inherited on the same chromosome
- MNS and P/Glob
- Kell and Kidd
- Duffy and Rh
- Lutheran and ABO

Answer 6

Duffy and Rh (1 and 1)
- MNS: 4
- P/Glob: 22 and 3
- Kell: 7
- Kidd: 18
- Lutheran: 19 (same as lewis)
- ABO: 9

Question 7

which listed are susceptible to enzyme treatment
- Rh
- Kell
- Kidd
- Duffy
- Lewis
- MNS
- P/Glob
- Lutheran

Answer 7

Duffy and MNS
- all others enhanced
- lutheran DTT destroyed

Question 8

If a patient has an unexpected antibody causing a reverse type discrepancy, which antibody is least likely
- I
- M
- P
- s

Answer 8

little s
- anti-I present in nearly everyone
- anti-M is IgM and will react at room temp
- anti-P is a cold reactive IgM and will react at room temp
- anti-s is IgG and will react in AHG

Question 9

Due to it being the second most immunogenic blood group system (besides Rh), which blood group is phenotypically matched to cells to sickel cell patients
- duffy
- kidd
- kell
- lutheran

Answer 9

Kell
- on antigram from left to right goes most immunogenic to least, kell is right after Rh

Question 10

what disease is associated with Duffy
- malaria Vivax
- Hydrops Fatelis
- delayed hemolytic transfusion reactions
- Paroxysmal cold hemoglobinuria

Answer 10

vivax

Question 11

what disease is associated with Kidd
- malaria Vivax
- Hydrops Fatelis
- delayed hemolytic transfusion reactions
- Paroxysmal cold hemoglobinuria

Answer 11

delayed hemolytic transfusion reaction

Question 12

what disease is associated with Rh
- malaria Vivax
- Hydrops Fatelis
- delayed hemolytic transfusion reactions
- Paroxysmal cold hemoglobinuria

Answer 12

Hydrops fatalis

Question 13

what disease is associated with P/Glob
- malaria Vivax
- Hydrops Fatelis
- delayed hemolytic transfusion reactions
- Paroxysmal cold hemoglobinuria

Answer 13

Paroxysmal cold hemoglobinuria
- anti - P: IgM, Donath landsteiner Ab
- P antigen also related to Parvo

Question 14

A patient has an antibody reactive with 8 out of 10 cells at room temp. It is enzyme resistant and neutralized by cyst fluid. Which antibody do you suspect
- anti-N
- anti-P1
- anti-P1PPK
- anti-IH

Answer 14

anti-P1: 80% frequency, IgM and is enzyme enhanced
- PIPPK is IgG

Question 15

how many panel cells containing E antigen need to demonstrate a positive agglutination reaction with the unknown antibody in order to statistically rule-in anti-E
- 1
- 2
- 3
- 4

Answer 15

3
- rule of 3 rule in or out

Question 16

what would you call the procedure where you mix patient plasma and patient cells, then read/grade reactions at IAT phase
- phenotype
- DAT
- auto control
- antibody ID

Answer 16

auto control
-> determining if patient is reacting to their own cells

Question 17

which circumstance(s) does NOT require phenotype testing
a. an Rh negative patient with a newly identified anti-D
b. recently transfused patient with known anti-Fya
c. units for a patient with known anti-K
d. units for a patient with a low incident antibody

Answer 17

a, b and d

Question 18

an antibody is clinically significant when (multiple possible)
a. it may cause transfusion reaction
b. it does not cause HDN
c. it is high incident
d. it is identified as an HTLA

Answer 18

a. it may cause transfusion reaction
-> HTLA = high titer low avidity, weakly reactive at big titer but won’t cause HDN or TRXN
-> M is high incidence but ignored due to non HDN or TRXN causing (IgM)

Question 19

which of the following neutralizing substances is accurately matched to its antibody
- breast milk: P
- normal human plasma: Chido/Rogers
- hydatic cyst fluid: lewis
- saliva: I

Answer 19

normal human plasma: Chido Rogers
- Hydatid: P1
- saliva: lewis
- urine: sfa
- human breast milk: I

Question 20

in which of the following procedures would a positive agglutination reaction complete your workuo
- rule in
- rule out
- phenotype testing of donor cell
- phenotype testing of patient cell

Answer 20

rule in

Question 21

MCleod syndrome is associated with nulls of which group

Answer 21

kell
- acanthocyes and chronic granulomas disease

Question 22

which of the followign atnigens appears on the antigram but does not need to be ruled out unless suspected because it is low incident
- Kpa
- K
- lna
- Xga

Answer 22

Kpa

Question 23

you are attempting to differentiate anti-S from anti-M which of the following information is most helpful

Answer 23

patient has an ABO discrepancy of extra reactions in reverse type
- MN is IgM and cold reacting
- S is IgG and warm reacting

Question 24

for what purpose would you choose a heterozygous cell
- rule out
- rule in
- positive control of phenotype
- negative control for phenotype

Answer 24

positive control of phenotype