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IMHM > AB Screening & ID > Flashcards

AB Screening & ID Flashcards

1
Q

detection & ID of AB against RBC AG; critical in PRE-TRANSFUSION SETTINGS

A

Antibody Screening & ID

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2
Q

principal tool for investigating potential HTR, AIHA, HDFN

A

Ab Screening & ID

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3
Q

_______aids in detecting and monitoring patients who are at risk of delivering infants with HDFN; The ony ig that can cross the placenta, associated with this disease is _______.

A

Ab Screening/ID

IgG

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4
Q

Focus of Ab Screening & iD

A

Detection of UNEXPECTED IRREGULAR ALLOANTIBODIES

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5
Q

4 types of unexpected irregular alloantibodies

A
  1. Ab reacting to transfused blood.
  2. Naturally occurring
  3. Acquired Ab
  4. AutoAb
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6
Q

Explain occurrence of
Ab reacting to transfused blood.

A

in response to RBC STIMULATION through transfusion, transplantation, pregnancy

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7
Q

Explain occurrence of
Naturally occurring unexpected immune allonantibodies

A

no RBC stimulation

through exposure to environmental surfaces/sources that have similar structure to RBC Ag

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8
Q

examples of environmental surfaces/sources causing naturally occurring unexpected immune allonantibodies

A

pollen
fungus
bacteria

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9
Q

Explain occurrence of
acquired unexpected immune allonantibodies

A

from one individual to another via plasma-containing blood components/derivatives.

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10
Q

example of plasma-containing bloodcomponents/derivatives causing naturally occurring unexpected immune allonantibodies — which is a treatment of choice for AB DEFICIENCIES

A

Intravenous Immunoglobulin [IVIG]

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11
Q

Explain occurrence of
Autoantibodies

A

against own antigens & generally react with all RBCs tested

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12
Q

it involves the reaction between px serum/plasma with screening cells.

A

Ab screening

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13
Q

Purpose is to detect RBC unexpected alloantibodies other than the expected anti-A and anti-B

A

Ab screening

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14
Q

Method of AB Screening

A

Indirect Antihuman globulin test

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15
Q

4 components of IAT

A

IS phase
AHG phase
Monospecific anti-IgG AHG reagent
37C

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16
Q

RBC reagent of IAT
[explain chracteristics]

A

Screening Cells
-Group O Ab + clinically unique combi of clinically important RBC Ag: 2-3 phenotypes

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17
Q

2-3 phenotypes combines with Group O Ab for screening cells

A

2:
R1R1 DCe
R2R2 DcE

3:
R1R1
R2T2
rr dce

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18
Q

why is Group O antigen used as a component of screening cells?

A

has no Ag in rBC no reaction and anti-a/b will not interfere

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19
Q

the homozygous expression w/in the screening cells allows Ab show ____.

A

dosage

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20
Q

Each set of screen cells is accompanied by:

A

Ag profile sheet/antigram

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21
Q

Antibodies that react strongly w/ cells having homozygous antigen expression

A

Ag profile sheet/antigram

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22
Q

antigen expression is from an individual who inherited 2 different alleles at a given genetic locus.

A

Heterozygous

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23
Q

The alleles share the available antigen sites on the cell surface.

A

Heterozygous

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24
Q

antigen expression is from an individual who inherited only one allele at a given genetic locus

A

Homozygous

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25
Q

Common Blood Group Systems
With Antibodies That Exhibit Dosage (Homozygous blood group)

A

Rh [except D[
Kidd
Duffy
MNS
Lutheran

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26
Q

Explain the process of IAT for AB Screening

A
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27
Q

if there is no sensitization nor agglutination in IAT, what do we add?

A

Check cells/Coomb’s reagentI

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28
Q

If after the addition of coomb’s reagent or check cells, what are the usual problems and what do we do about it>

A

During testing problems/ error [AHG. not added]

REPEAT

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29
Q

RBCs become “IgG-coated RBC’’ due to the

A

Addition of an enhancement reagent that triggers the px’s serum containing [IgG] to target the known RBC reagent/Screen cell which possesses a known antigen making it the targetq

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30
Q

Effect of AHG reagent addition after NSS washing in IAT

A

The anti-IgG in it will react w/ the IgG-coated RBC resulting to cross-linking and forming a BRIDGE where observable AGGLUTINATION occurs

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31
Q

OTHER METHODS USED FOR ANTIBODY SCREENING:

A

Gel Method
Solid phase adherence method

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32
Q

Gel Method Principle

A

If sensitization occurred, anti-IgG IN THE GEL will REACT with the sensitized rbcs resulting in agglutination

Agglutinated cells will be TRAPPED within the gel because agglutinates are too large to pass the spaces between gel particles

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33
Q

Agglutinated cells in the Gel Method will be TRAPPED within the gel because

A

they are too large to pass the spaces between gel particles

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34
Q

Grade?

cell top: SOLID BAND of agglutinates
bottom: #red cells visible

A

4+

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35
Q

Grade?

LOWER-half gel column: agglutinates
bottom: red cell [above red cell pallet: few agglutinates]

A

1+

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36
Q

Grade?

top of gel column: ag DISPERSED
bottom: few agglutinates

;distributed through upper/lower halves of gel

A

2+

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37
Q

Grade?

top gel column: LAYER of red cell agglutinates
bottom: PELLET of UNAGGLUTINATED CELLS

A

Mixed-field

38
Q

Grade?

bottom: rbc forming a WELL-DELINEATED PALLET
[Above pallet] CLEAR/FREE agglutinates

A

NEGATIVE

39
Q

Grade?

top gel column: #amount of agglutinates
bottom: few agglutinates

A

3+

40
Q

Components of Gel method

A

6 chambers/gel
Dextran Acrylamide gel
Screen Cells + Px serum/plasma

37C 15mins

41
Q

Principle of Solid Phase Adherence Method

A
  1. RBC Ag-COATED microtiter wells
  2. Px serum/plasma + LISS added
    37C incubation
  3. Washed to remove unbound Ab
    4.
    AHG-coated RBCs [indicator] added
  4. POSITIVE= AHG react w/ Ab-Ag bound
    NEGATIVE=AHF form a PELLET in the bottom
42
Q

Done when the antibody screening test is positive to _____ the alloantibody

A

AB ID

Identify

43
Q

IAT may or may not include this as a detection for the AB reacting at room temp; not required as it leads to clinically [significant/insignificant] [cold/warm] Ab

A

Immediate spin phase

Insignificant
Cold

44
Q

AB ID uses what:

cells:
material:
methods:

A

panel cells [group O, 11-20 extended screening cells]

Ag profile sheet/antigram

DAT
autocontrol

45
Q

Steps in AB ID

A
  1. Know the Px HISTORY
  2. Check RXN phase w/ positive agglutination
  3. Check AUTOCONTROL
  4. Exclusion
  5. Inclusion
  6. Perform ADDT’L techniques
    [Selected Panel cells, Neutralization, Adsorption, Elution]
    7.CONFIRM result by 3 & 3 RULE
46
Q

Enumerate what to consider in Px history

A

Age
Sex
Race

Diagnosis
Pregnancy history

Medications
IV solutions

47
Q

Race: can be beneficial because some antibodies are associated with a particular race.

anti-__ – blacks
anti-__ – Africans)

A

Fya

U

48
Q

Transfusion and pregnancy: exposure can cause ______ of immune antibodies

A

production

49
Q

Medications to take into consideration as they may transfer PASSIVE AB [anti-A/B/D]

A

IVIG
RhIg
Anti-lymphocyte globulin

50
Q

administer to Rh negative mother with an Rh positive baby

A

rhogam

51
Q

animal antibody against human T cells that is used in treatment for acute rejection in organ transplantation

A

Anti-lymphocyte globulin

52
Q

Infections and autoimmune disorders can cause production of ______

A

autoantibodies

53
Q

Patients transfused in the last 3 months (DHTR) can also cause a _______

A

POSITIVE DAT

54
Q

3 and 3 rule meaning

A

3 positive
3 negative

55
Q

________
Additional panel cells that are added to help in identifying antibodies

2 or 3 can be used but we can still add. _____ panel cells can be used

A

Selected Panel Cells

11-20

56
Q

Treating the panel cells with enzymes may help separate the __________ and allow antibody ________

A

specificities

identification

57
Q

Examples of enzymes used as an additional technique for AB ID
[general]
[specific]

A

Proteolytic enzymes
[papain, bromelin, trypsin]

58
Q

Proteolytic enzymes modify the rbc surface by removing the ________ and by denaturing or removing _______.

A

sialic acid residues

glycoprotein

59
Q

antigens enhanced by enzymes

A

Rh
Kidd

Lewis
P1
I
ABO

60
Q

antigens activated by enzymes

A

Duffy
MNS

Xga

61
Q

Other substances in the body and in nature have antigenic structures similar to antigens

A

Neutralization

62
Q

Soluble substances can be used to _______ antibodies in serum, allowing ________ of antibodies or confirmation that a particular ______ is present.

A

neutralize

seperation

antibody

63
Q

inhibit reaction between antibody and antigens on panel cells

A

Soluble substances

64
Q

Anti-P1
Source of neutralizing substances

A

Hydatid cyst fluid
Pigeon droppings
Turtledoves egg whites

65
Q

Anti-Lewis
Source of neutralizing substances

A

Plasma/Serum
Saliva

66
Q

Anti-Chido/Rogers
Source of neutralizing substances

A

Serum [+complement]

67
Q

Anti-Sda
Source of neutralizing substances

A

Urine

68
Q

Antii-I
Source of neutralizing substances

A

Human breast milk

69
Q

Removal of antibodies from serum by adding the target antigen allowing antibody to bind to the antigen

A

Adsorption

70
Q

In adsorption, Antigen-antibody complexes is removed from the test system by ______.

A

centrifugation

71
Q

________ is tested against panel cells for the presence of unabsorbed alloantibodies

A

Adsorbed serum

72
Q

Adsorbed serum is TESTED AGAINST PANEL CELLS for the presence of unabsorbed alloantibodies. THROUGH? [application steps]

A
  1. remove non-specific ab from serum
  2. seperate mixtures of ab [to aid their [ID]
  3. determine [+] alloantibody/autoantibody in a px w/ HEMOLYTIC ANEMIA
73
Q

Types of Adsorption

A

Autologous
Homologus Adsorption
Differential Adsorption

74
Q

simplest method of absorption

A

AUTOADSORPTION

75
Q

In autoadsoprtion,

warm ab is adsorbed at what temp?

cold ab is adsorbed at what temp?

A

37C

4C

76
Q

Autoadsorption steps

A
  1. Autologous washed [remove unbound ab]
  2. Cells treated [remove any Ab-coating RBC]
  3. Cells incubated w/ px serum for up to 1 hour [30-60 mins]
    [Temp: thermal-range of removed-Ab]
    [During incubation: mix periodically]
    [X AB @serum –> ADSORBED @RBC]

4.
Adsorbed serum then harvested
& Tested against Panel cells

5.
DAT[-] autologous cells–

If REACTIVE = further adsorption
using a new aliquot of autologous required.

If NON-reactive=
autoantibody completely adsorbed + adsorbed serums can be used in antibody identification testing.

77
Q

DAT[-] autologous cells–

If REACTIVE = _______

If NON-reactive=
___________

A

further adsoption [using new aliquot of autologous cells]

Autologous completely adsorbed
+Adsorbed serums can be used in AB ID TESTING

78
Q

used to remove, concentrate, purify AB from RBCs

A

Elution

79
Q

This is being performed when DAT is positive

A

Elution

80
Q

diluent where removed ab from RBCs are harvested/tested against panel cells

A

Eluate

81
Q

ab removed from RBCs
& RBC Ag are destroyed

A

Total elution

82
Q

ab removed
RBC Ag remain intact [RBC ______ & used for autoadsorption techniques.

A

Partial elution

83
Q

Elution Application:

A

—Demonstrate & Identify Ab on the RBC of HDN, HTR,AIHA

— Seperate & Identify Ab IN A MIXTURE OF AB

84
Q

Elution Methods

A

Temperature

pH

Organic solvents

85
Q

Elution Temperature Method:

HEAT
45C:

56C:

FREEZE
RBCs are washed/suspended in ______ and frozen at [temp].
Mixture is _____ rapidly bursting _____ freeing the ab

A

Gentle heat method/Partial Elution

Total elution/ elute ABO Ab from RBC

saline
18C
thawed
RBCs

86
Q

Elution method

pH
[Acid/Alkaline] elution:
washed ______rbcs are mixed w/ _________ [ph__]–> then released into the ______.

A

Acid elution
Ab-coated
glycine acid
3
supernatant

87
Q

Elution method

Organic solvents
[Partial/Total] elution; best for detecting non-ABO Ab: [3]

A

Total

dichloromethane
xylene
ether

88
Q

Done to determine the relative
amount of antibody in the serum

A

Ab Titration

89
Q

expressed as the reciprocal of the highest dilution with macroscopic agglutination

A

Titer

90
Q

Elution Method

Ig TYPING

Uses ________ reagents which inactivates ____ leaving IgG intact.

Used to break agglutination by strong _________

DTT, 2-ME, AET

A

sulfhydryl reagents
IgM

IgM cold autoantibodies

91
Q

Reagents used in Ig Typing method of elution

A

ZZAP
DTT
2-ME
AET

92
Q
A

IMHM (4 decks)

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