mmsc 421 bloodbank lab quiz 1

the recommended range for red cell suspensions is ___________________

a) 5-6%

b) 1-3%

c) 2-3%

d) 2-5%

d) 2-5%

explain what happens if the cell suspension falls outside of the recommended range (both above and below)

if the cell suspension is above range, it may show a false positive result, nonspecific agglutination

if the cell suspension is below range, it may show a false negative result

what is an "eyeball" 2-5% red blood cell suspension

suspension measured by it's "cherry red" color

rbc mixed and washed with saline

when performing an ABO (red cell) forward grouping test, ____________ drop(s) of ____________________ is added to __________ drop(s) of __________________.

one

2-5% rbc suspension

one

antisera

when performing an ABO (serum) reverse grouping test, ____________ drop(s) of ______________ is added to ___________ drop(s) of ____________________

one

reagent cells

two

patient serum/plasma

cord blood samples may be contaminated with ____________________ and thus must be washed before cell typing can be performed

a) Wharton's jelly

b) saline

c) placenta

d) mucous

a) Wharton’s jelly

ABO _____________ grouping cannot be perfromed accurately on neonates less than 6 months of age since they do not possess __________________.

a) forward; antibodies

b) reverse; antibodies

c) forward: antigens

d) reverse; antigens

b) reverse; antibodies

If ABO phenotype is A... fill in blank

Anti-A _____________

Anti-B ________________

Anti-A1B _____________

pos

neg

pos

if ABO phenotype is B... fill in blank

Anti-A _____________

Anti-B ________________

Anti-A1B ______________

neg

pos

pos

if ABO phenotype is O... fill in blank

Anti-A _____________

Anti-B ________________

Anti-A1B _____________

neg

neg

neg

if ABO phenotype is AB... fill in blank

Anti-A _____________

Anti-B ________________

Anti-A1B _____________

pos

pos

pos

looking at results, interpret ABO phenotype

A1 cells: neg. B cells: pos

A1 cells: pos. B cells: pos

A1 cells: pos. B cells: neg

A1 cells: neg. B cells: neg

A

O

B

AB

what is an ABO discrepancy?

when forward type doesn't match reverse type

explain the purpose of the D control

ensures reagents are working as needed and the procedure is being done correctly

confirm a patient is truly D neg.

what is weak D test and when is it performed?

performed when a patient/donor's cells test D negative. it is done to ensure it is truly D negative and not weakly positive. washes cells of excess stuff that could interfere with the reaction leaving just red cells.

describe the weak D test as an example of an indirect antiglobulin test (IAT)

weak D testing adds red cells to test for antigens not antibodies making it an indirect test. it tests for sensitized rbc.

discuss the purpose of check cells in weak D test (IAT)

to ensure a true negative. check cells should always come back positive. If not, it could indicate a weak positive or microscopic agglutination, or that the procedure wasn't done right

discuss a possible cause for a positive D control when using high-protein anti-D reagents

different manufacturers cold use different additives in their control cells vs anti-D reagents. if two different manufacturers were used for the reagent and control, it could result in a pos D control which is why there is a need to use the same manufacturer for this test. D controls should be negative.

when performing an antibody screen, each tube (containing serum and cells) must be observed for both ____________ and _____________

agglutination

hemolysis

an antibody screen is performed to detect

a) expected clinically significant alloantibodies

b) unexpected clinically significant alloantibodies

c) autoantibodies

d) known red cell antigens

b) unexpected clinically significant alloantibodies

manufacturer's screening cells are of the blood group

a) A

b) B

c) AB

d) O

d) O

the specimen of choice for antibody screening is

a) serum

b) plasma

a) serum

when performing an antibody screen, ________ drop(s) of patient serum and _____________ drop(s) of manufacturer's screening cells are used.

2

1

explain why an antibody screen does not detect ALL antibodies

some antibodies are so rare they are clinically insignificant

identify the three phases of testing used in performing an antibody screen

a) SALINE, 37C, WASH

b) immediate spin (IS), 37C, AHG

c) immediate spin (IS), LISS, WASH

d) LISS, WASH, AHG

b) immediate spin (IS), 37C, AHG

is it acceptable to repeat only the final phase of the antibody screen if the check cells do not "check" (neg reaction)

a) yes

b) no

b) no

T/F: a positive antibody screen indicates the presence of one or more antibodies directed at antigens present on the particular screening cell or cells

a) true

b) false

a) true

T/F: a positive antibody screen indicates the need for antibody identification

a) true

b) false

a) true

to "rule in" the presence of an anti-E in a patient's serum, at least _________ of the panel cells which which the patient's serum reacted (agglutinated) with must be ___________ for the E antigen

a) 3; negative

b) 1; negative

c) 1; positve

d) 3; positive

d) 3; positive

which of the following is an example of a homozygous C cell?

a) C+c+

b) C-c-

c) C+c-

d) C-c+

c) C+c-

except for autoantibodies and rare antibody-like substances, a patient's cells should be ________________ for the antigen corresponding to the antibody detected in the patient's serum

a) negative

b) positive

a) negative

a patient was transfused one month ago. can his cells be accurately phenotypes?

a) yes

b) no

c) need more information

b) no

antigen phenotyping with anti-E, chose the correct cell for the positive control

a) E-e-

b) E+e-

c) E-e+

d) E+e+

d) E+e+

which of the following can cause an incompatible crossmatch?

a) contaminant in the test system

b) ABO error

c) alloantibody directed toward antigen on donor rbc

d) all answers are correct

d) all answers are correct

a unit of donor blood which gave a positive reaction (agglutination) when tested with recipient's serum (crossmatch) is said to be ______________

a) incompatible

b) compatible

c) an autoantibody

d) need more info

a)incompatible

choose the best answer for the below results

anti-A: 0

anti-B: 3+

anti AB: 3+

A cells: 0

B cells: 0

O cells: 0

auto control: 0

a) subgroup of A

b) acquired B antigen

c) neonate

d) alloantibody

c) neonate

choose the best answer for the below results

anti-A: 3+

anti-B: 0

anti AB: 3+

A cells: 1+

B cells: 3+

O cells: 0

auto control: 0

a) subgroup of A

b) A2B with anti-A1

c) alloantibody

d) A2 with anti-A1

d) A2 with anti-A1

choose the best answer for the below results

anti-A: 0

anti-B: 3+ (mf)

anti AB: 3+ (mf)

A cells: 4+

B cells: 0

O cells: 0

auto control: 0

a) alloantibody

b) 2-cell population

c) bombay

d) acquired B antigen

b) 2-cell population

choose the best answer for the below results

anti-A: 3+

anti-B: 3+

anti AB: 3+

A cells: 0

B cells: 2+

O cells: 2+

auto control: 0

a) autoantibody

b) subgroup of A

c) auto anti-I

d) alloantibody

d) alloantibody

choose the best answer for the below results

anti-A: 3+

anti-B: 3+

anti AB: 3+

A cells: 0

B cells: 0

O cells: 0

auto control: 2+

a) autoantibody

b) neonate

c) A2B with anti-A1

d) alloantibody

a) autoantibody

routine blood bank reagents must be checked for reactivity how often?

a) twice per shift (12 hours)

b) once per shift (8 hours)

c) daily

d) weekly

c) daily

which cells are helpful in identifying the cause of an ABO discrepancy

a) A1 cells and B cells

b) A2 cells

c) screening cells

d) all of the above

d) all of the above

name the lectin(s) helpful in identifying the cause of an ABO discrepancy

a) anti-H lectin

b) anti-A1 lectin

c) anti-B lectin

d) both anti-A1 and anti-H lectin

d) both anti-A1 and anti-H lectin

which is a cause of ABO discrepancy which manifests itself through a red cell inconsistency (forward grouping)

a) patient has immunodeficiency

b) infant less than 4 months of age

c) weakly expressed A or B antigens

d) elderly person whose antibodies have declined

c) weakly expressed A or B antigens

which is a cause of ABO discrepancy which manifests itself through a serum inconsistency?

a) previous non group specific transfusion

b) weakend A or B antigens in leukemics

c) polyagglutinable rbc

d) infant less than 4 months of age

d) infant less than 4 months of age