AHG Test Flashcards

1
Q

Also knowns COOMBS Test

A

Antihuman Globulin Test

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2
Q

detects non-agglutinating antibody by means of COUPLING WITH SECONDARY ANTIBODY

A

AHG TEST

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3
Q

It bridges the distance between cell that IgG alone cannot do

A

Antihuman globulin

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4
Q
  • In VIVO attachment
  • Uses RED CELL as specimen
A

Direct AHG Test

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5
Q

Anticoagulant used in DAT

A

EDTA

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6
Q

What is preferred EDTA in DAT pink OR violet

A

PINK

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7
Q

AHG TEST USED IN:
1. Investigation of HTR
2. Investigation of HDN
3. Investigation of AIHA
4. Diagnosis of Drug-induced

A

DAT

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8
Q
  • Non-agglutinating antibody
  • sensitized and coat with Red cells
  • without causing agglutination
A

IgG

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9
Q

Drug-Induced Hemolytic Anemia:

Drug Absorption

A

Penicillin

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10
Q

Drug-Induced Hemolytic Anemia:

Membrane modification

A

Cephalosphorin

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11
Q

Drug-Induced Hemolytic Anemia:

Immune-complex

A

PaRa Sa Immune-complex

Phenacetin
Rifampin
Stibufen
Quinidine

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12
Q

Drug-Induced Hemolytic Anemia:

Autoantibody formation

A

Methyldopa (Aldomet)
Mefenamic acid

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13
Q

Increased OFT ; Increased MCHC

are both observed in Hereditary Spherocytosis and AIHA. What is the test needed to differentiate the two?

A

DAT

Hereditary Spherocytosis (-)
AIHA (+)

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14
Q

AHG Reagent specifically binds on the __ portion of IgG

A

Fc portion

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15
Q
  • Determines the presence of PARTICULAR ANTIBODY in patient
  • In VITRO sensitization
  • uses SERUM/PLASMA spx
A

IAT
(Indirect AHG Test)

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16
Q

AHG TEST used in:
1. Crossmatching
2. Antibody detection
3. Antibody Identification
4. RBC Phenotyping

17
Q

Anticoagulant used for IAT

A

NONE
Red top tube

18
Q

2 PROCESS OF IAT

A
  1. Washed RBC and Antibody are allowed to combine at 37 deg cel
  2. Washed RBC again 3x and add AHG Test
19
Q

Washing of RBC is require to

A

remove unbound antibody

20
Q

Presence of unbound antibody effect

A

neutralizes AHG Reagent

21
Q

AHG reagent color

22
Q
  • consist of anti-IgG AND anti-c3d
  • obtained from RABBITS
A

Polyspecific AHG

23
Q
  • consist of anti-IgG OR anti-c3d
  • obtained from MICE
A

Monospecific AHG

24
Q

If (+) for Monoclonal AHG,sample is subject for

25
Patient with AIHA coats the patient cells with warm IgG antibody , thus requires
Removal of antibody from RBC for accurate RBC phenotyping
26
Techniques used to Remove Antibody from RBC
1. Chloroquine 2. EDTA-glycine 3. Murine monoclonal antibodies
27
- used to validate NEGATIVE RESULT OF AHG TEST - uses Group O sensitized with IgG
Check O cells
28
Check O cells (+) agglutination means:
1. AHG was added 2. AHG was not neutralized If (-) check cells then INVALID TEST
29
1. contamination of reagents 2. Overcentrifugation 3. Direct agglutination of strong agglutinin 4. Over-incubation 5. Improper use of enhancement reagents 5. Saline stored in glass or metal containers
False POSITIVE (+) AHG
30
1. Reagent failure 2. Failure to add AHG reagent 3. Improper WASHING 4. Improper centrifugation 5. Serum/Cell ratio TOO LOW 6. Delay in washing
False NEGATIVE (-) AHG
31
Elution of weakly attached Antibody is due to
Delay in washing
32
Enhancement Reagent for AHG (4)
1. Albumin 2. Polybrene 3. Low Ionic Strength Solution (LISS) 4. Polyethylene Glycol (PEG)
33
Enhancement Reagents that shortens the incubation time for 10-15 mins
LISS PEG