Anti Human Globulin Test ( Chapter 5 ) Flashcards Preview

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1

Anti Human Globulin Test is also known as

Coomb's Test

2

This antibodies are also termed as nonagglutinating or incomplete antibodies

IgG antibodies

3

Where does the AHG binds ?

It binds to the Human Globulins such as IgG or Complement either in free serum or attached to the antigen of the RBC

4

In what year does Coombs and associate describe the use of the antiglobulin test for the detection of weak and nonagglutinating Rh antibodies in serum

1945

5

What is the purpose of Absorption in the procedure for AHG

To remove heterospecific antibodies

6

What is the purpose of Dilution in the procedure for AHG

to avoid prozone

7

First Blood Group System that were reported only weeks after Coomb's had described the test

Kell Blood Group System

8

It is based on the principle that antihuman globulins obtained from immunized nonhuman species bind to human globulins

Anti-Human Globulin Test/Coomb's Test

9

First to describe the principle of Coomb's Test

Moreschi 1908

10

Early AHG reagents were prepared using a crude globulin fraction as the _____.

Immunogen

11

Presented the first indication that there might be another antibody activity present that influenced the final reaction in AHG test

Dacie 1951

12

The AHGT can be used to detect RBC sensitized with _____ , _______ and ___________

IgG alloantibodies , IgG autoantibodies and complement components.

13

In AHG reactivity cell sensitized with cold antibodies is resulted from what type of Globulin Activity

Anti-NonGamma Globulin activity

14

In AHG reactivity cell sensitized with warm antibodies is resulted from what type of Globulin Activity

Anti-Gamma Globulin activity

15

NonGamma Globulin component is believe to be what type of globulin

Beta Globulin

16

The use of AHG to detect in vitro sensitization of RBC's in two-stage technique is referred as

Indirect Anti-Globulin Test

17

In vivo sensitization is detected by one stage procedure called

Direct Anti-Globulin Test

18

Give 3 AntiHuman Globulin Reagents that are Polyspecific

1.Rabbit Polyclonal
2.Rabbit/Murine monoclonal Blend
3.Murine Monoclonal

19

Give 3 AntiHuman Globulin Reagents that are Monospecific

1,Rabbit Polyclonal
2.IgG heavy chain specific
3.Monoclonal IgG

20

A Polyspecifc AHG RGt. that contains rabbit polyclonal Anti-IgG and Murine monoclonal anti-C3d and anti-C3b

Rabbit/Murine monoclonal Blend

21

A monospecific AHG RGT that contains only antibodies reactive againts Human Gamma Chains

IgG Heavy Chain specific

22

What are the licensed monospecific AHG that are commonly use

Anti-IgG and anti-C3b-C3d

23

If Polyspecific AHG Rgt. reacts with IgA and IgM molecules what type of chain is responsible for this reaction

Light Chain Kappa and Lambda

24

Anti-IgG reagents contain antibodies specific to Fc fragment of what type of chain

Heavy Gamma Chain

25

A technology that can be used to produced monoclonal antiglobulin serum.

Hybridoma Technology

26

Are derived from one clone of plasma cells and recognize a single epitope

Monoclonal antibodies

27

Who devised the monoclonal antibody technique

Kohler and Milstein

28

The only IgG subclass that has no clinical significance in AHG test

IgG4

29

If large volume is needed in Polyclonal AHG technique what animal would you use?

Goat or Sheep

30

AHG reagents that contain only one antibody specificity either anti-IgG or antibody specific complement components such as C3b or C3d

Monospecific AHG RGT

31

In monoclonal AHG production antibody is collected as

Ascites

32

True or False . Monoclonal AHG production needs absorption to remove heteromorphic antibody

False it does not need Absorption

33

In monoclonal AHG production how can u give potent rgt. that give a fewer false positive reactions .

Monoclonal Antibodies to human complements Anti-C3b and Anti-C3d may be blended with POLYCLONAL anti-IgG from rabbits.

34

Animal use in Monoclonal AHG production

Mice

35

13 Most Antibody that fix complements

A-Le-Le-Sc1-Jk-Jk-Co3-Ge2-Ge3-li-Vel-P-PP1Pk

36

Considered to be the most important anticomplement component because of its limited capacity to cause nonspecific rxn.

Anti-C3c

37

AHG Rgt. should be dyed in what color for identification

Green

38

Serum to Cell ratio

2:1

39

Antibody to Antigen ratio

40:1

40

Indirect Antiglobulin Test is used in the ff. situation

Detection of incomplete(nonagglutinating) antibodies to potential donor RBCs ( compatibility testing ) or to screening cells ( antibody screen ) in serum
Determination of RBC phenotype using known anti sera
Titration of incomplete antibodies

41

Determinant of Immunoglobulin classes

CH3 portion of the heavy gamma chain

42

4 uses of Direct Antiglobulin Test

HDN
HTR
AIHA

43

How many times would you wash RBC

3 times

44

DAT can detect how many IgG and C3d

100-500 IgG molecules per RBC
400-1100 molecules C3d per RBC

45

IAT can detect how many IgG and C3d

100-200 IgG and C3 molecules per RBC

46

Factors affecting AGT

R
R
T
I
W
S
A
C

47

Source of false positive in AGT

I
A
B
C
S
D
O
P
P
C

48

3 types of Reaction mediums

22% Bovine Albumin
LISS
PEG

49

Recommended method for the evaluation of AHG centrifugation time

1000 RCF in 20seconds

50

Saline is buffered to a pH of _______

7.2 - 7.4

51

The usual incubation temperature for the IAT

37*C

52

The optimum temp for complement activation

37*C

53

Incubation time for LISS

10-15 mins

54

Incubation time using 22% bovine albumin

30 mins

55

are macromolecule additive used with LISS to bring sensitized RBCs closer to each other to facilitate cross-linking and agglutination rxn .

PEG and Polybrene

56

DAT incubation temperature

Room Temp 16-22*C

57

Is a process that detects RBC antigen-antibody rxn by means of using a chamber filled with polyacrylamide gel

Gel Test

58

It is a potent rouleaux forming reagent

Polybrene

59

enummerate 4 modified and automated AGT techniques

LIP
ELAGT
SPT
Gel Test

60

An anticoagulant used to collect samples for the DAT to avoid in vitro complement attachment associated with refrigerated clotted specimens

EDTA

61

In ELAGT what is the usual OD

405 nm

62

3 types of Gel Test

Neutral
Specific
Antiglobulin

63

IgG subclasses that strongly binds to the complement

IgG 1 and IgG 3

64

Drug induces Ab that binds to RBC only when drug is present in soluble form , unknown mechanis,

Type 3 (Drug Dependent)

65

Ab reacts with normal RBCs when soluble drug is present

Type3 (Drug Dependent)

66

Drug binds covalently to membrane proteins and stimulates hapten dependent Ab

Type 1 (Hapten Ab dependent)

67

Drug induces autoantibody specific for RBC membrane protein through unknown mechanism

Type 2 ( Autoantibody)

68

Type of Drug induce wherein Ab reacts with normal RBC in the absence of drug

Type 2

69

Autoantibody reacts with patients RBC in in vivo

WAIHA

70

Cold reactive IgM autoagglutinins binds to RBCs in peripheral circulation (32*C)

CAS

71

The IgG autoantibody reacts with colder part of body, causes complement to be bound irreversibly to RBCs and then elutes to warmer temp

PCH

72

IgM binds completely as RBCs return to warmer parts of the circulation

CAS

73

IgM dissociates leaving RBCs coated only with complement

CAS