2S [LEC]: Antihuman Globulin Test Flashcards by 3sha Ann

Q

In 1908, which scientist described the principle of the AHG test?

A

Moreschii

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Q

In 1945, which scientist described the use of the antiglobulin test for the detection of weak and non-agglutinating Rh antibodies in the serum?

A

Robert Russell Race

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Q

In 1946, which scientist described the used of AHG to detect in vivo sensitization of the RBCs of babies suffering from HDN?

A

Coombs

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Q

The AHG reagent is composed of red cells sensitized by what?

A

IgG or C’ proteins (C3b or C3d)

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Q

The monoclonal antibody technique was devised by ___

A

Kohler and Milstein

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Q

Sample of choice for DAT

A

EDTA blood

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Q

Complement-dependent antibodies will not be detected when which specimen is used?

A

Plasma

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Q

Which reagent negates the in-vitro activation of the complement pathway?

A

EDTA

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Q

What would be the effect when an in vivo sensitization results to recipient antibody coating donor RBCs?

A

Hemolytic Transfusion Reaction (HTR)

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Q

Immune-mediated red cell destruction leading to anemia is a result when transfusion still proceeded in a positive test for which method?

A

DAT

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Q

Test employed to diagnose Paroxysmal Cold Hemoglobinuria

A

Donath Landsteiner Test

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Q

DAT result if a patient is positive for autoantibody

A

Positive

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Q

What would be the effect when an in vivo sensitization results to maternal antibody coating fetal RBCs?

A

HDFN

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Q

What would be the effect when an in vivo sensitization results to autoantibody coating individual’s RBC?

A

AIHA

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Q

Identify the type of drug-induced phenomena associated with a positive DAT:

Drug binds covalently to membrane proteins and stimulates hapten-dependent Ab

A

Type I (hapten-dependent Ab)

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Q

Identify the type of drug-induced phenomena associated with a positive DAT:

Drug induces autoantibody specific for RBC membrane proteins through unknown mechanism

A

Type II (Autoantibody)

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Q

Identify the type of drug-induced phenomena associated with a positive DAT:

Ab reacts with normal RBCs in the absence of drug

A

Type II (Autoantibody)

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Q

Identify the type of drug-induced phenomena associated with a positive DAT:

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

A

Type III (drug-dependent Ab)

Q

Identify the type of drug-induced phenomena associated with a positive DAT:

Ab reacts with normal RBCs when soluble drug is present

A

Type III (drug-dependent Ab)

Q

Samples used in IAT

A

Red cell or serum

Q

Procedure that detects antibodies with specificity to red cell antigens

A

Antibody screening

Q

Procedure that identifies specificity of red cell antibodies

A

Antibody identification

Q

Procedure that determines serologic compatibility between donor and patient before transfusion

A

Crossmatch

Q

Procedure that identifies a specific red cell antigen in a patient or donor

A

Antigen typing

Potentiator that cross-links IgG-sensitized red cells

AHG reagents

Potentiator that increases the rate of antibody uptake

LISS

Potentiator that concentrates the antibody in the test environment in LISS

PEG

Potentiator that removes negative charges from the red cell membrane, which reduces the zeta potential and denatures some red cell antigens

Proteolytic enzymes

Potentiator that requires 20-30 mins incubation

Albumin

Potentiator that requires 10 mins incubation

LISS

Potentiator that lowers ionic strength allowing better reaction

LISS

Potentiator that is sensitive and quick

LISS

Potentiator that enhances warm autoantibodies

PEG

Potentiator that does not react well with insignificant antibodies (IgM)

PEG

Potentiator that doesn't enhance warm autoantibodies

Albumin

The saline for washing is buffered at what pH level?

7.2 to 7.4

Shelf life of prepared saline for washing

30 days

Incubation time if LISS or PEG technique is utilized

10-15 mins

Result of extended incubation

Elution

T/F: Polyclonal antibodies have shown to have narrow pH ranges for optimum reactivity

False (monoclonal)

Saline stored for long periods in plastic container yields what erroneous result?

False negative

Effect of saline stored for long periods in plastic container

decreased pH, increased elution

Effect of inadequate resuspension

Weak false positive

Effect of resuspension being prepared too vigorously

False negative