Coombs Test (Direct or Indirect)

Last updated 20.09.12

 

Definition

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Features

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Types

- DAT

- Indirect

 

 

 

Direct Coombs Test (Direct Antiglobulin Test (DAT))

 

Rationale

- Used to detect antibodies or complement bound to RBCs

 

Procedure

- Venepuncture: blue tube

- Plasma removed

- RBCs incubated w Coombs reaganet (anti-human globulin)

- Agglutination = +ve

 

Indication

- Haemolytic anaemia

-  Haemolytic disease of newborn

-  Transfusion reactions

-  SLE

-  Infectious mononucleosis

-  Drug induced (Penicillin, methyldopa)

 

 

 

Indirect Coombs Test (Indirect Antiglobulin Test)

 

Rationale

- Used to detect antibodies against RBCs in serum, not bound to RBCs

- Used in prenatal testing

- Also used to test blood for transfusion

 

Procedure

- Patients serum incubated w RBCs of known anitgenicity

- RBCs incubated w Coombs reaganet (anti-human globulin)

- Agglutination = +ve

 

Indication

- Ab present in serum against tested RBCs

-  Autoimmune haemolytic aenaemia