Transfusion Serology

Immunohaematology and red cell serological tests are used to identify safe products for transfusion. These tests include:

Saline Agglutination

  • Sample of donor product and recipient cells are mixed in a saline suspension
  • Agglutination indicates ABO incompatibility

Antiglobulin Testing

Antiglobulin testing consists of either:

  • Direct Antiglobulin Testing
    Antiglobulin present on surface of patient erythrocytes. Positive in:
    • Autoimmune haemolytic anaemia
    • Haemolytic transfusion reactions
  • Indirect Antiglobulin Testing
    Antibody (usually IgG) present in plasma. Predominantly used in transfusion for:
    • Minor antibody detection
    • Pre-transfusion compatibility

Coombs test is:

  • Also known as antiglobulin testing
  • A test for autoantibodies against circulating erythrocytes
  • Diagnostic of autoimmune haemolytic anaemia
    Also used in identifying transfusion-relevant antibody.
  • Performed either by:
    • Direct antiglobulin testing
      • Detects antibodies bound to erythrocytes.
      • Patient blood washed in saline to remove plasma and unbound antibodies
      • Reagent added to detect bound IgG
    • Indirect antibody testing
      • Patient plasma mixed with foreign erythocytes of known antigenicity
      • Reagent added to detect patient antibody bound to foreign cells

References

  1. Bersten, A. D., & Handy, J. M. (2018). Oh’s Intensive Care Manual. Elsevier Gezondheidszorg.