Compatibility procedure before blood transfusion

compatibility procedure before transfusion

The main aim of pre-transfusion or compatibility tests is to ensure that potentially fatal haemolytic transfusion reactions are prevented and the best possible results of transfusion is achieved (1).

The process begins with the identification of the intended recipient and collection of a properly labelled blood sample in the ward. The compatibility tests include

• ABO and Rh grouping performed on the donor and recipient samples
  • ABO grouping is the single most important test performed on pre-transfusion samples and the sensitivity and security of testing systems must not be compromised
• screening patient’s and donor’s sera for unexpected antibodies
• cross match (1)

Group & screen

• patient’s pre transfusion blood is tested to identify the ABO and RhD groups and the plasma is screened for the presence of red cell alloantibodies capable of causing transfusion reactions
• blood with a compatible ABO and Rh group, negative for any blood group alloantibodies is selected form the blood bank
• blood grouping and antibody screening is carried out using automated analysers with computer control of specimen identification and result allocation to
• British Committee for Standards in Haematology (BCSH) guideline for pre-transfusion compatibility procedures (2012) recommends that a second sample should be requested for confirmation of the ABO group of a first-time transfused patient provided this does not impede the delivery of urgent red cells or components

Cross matching

• final step is to carry out a serological crossmatch between the patient’s plasma and a sample of red cells from the units of blood selected for transfusion
• performed by theindirect antiglobulin test (IAT) method at 37°C, looking for evidence of a reaction that would indicate incompatibility (2).

These procedures normally take about 1 hour to complete. Shortened procedures are possible, but may fail to detect some incompatibilities (3).

tests on blood donations (2)

At each donation, the following mandatory tests are performed:

• hepatitis B – HBsAg
• human immunodeficiency virus – anti-HIV 1 and 2 and HIV NAT (nucleic acid testing)
• hepatitis C – anti-HCV and HCV NAT
• human T-cell lymphotropic virus – anti-HTLV I and II
• syphilis – syphilis antibodies

Additional tests, performed in special circumstances, include:

• cytomegalovirus (CMV) antibodies
• Malarial antibodies
• West Nile Virus antibodies
• Trypanosoma cruzi antibodies

Reference:

• (1) Boisen ML et al. Pretransfusion testing and transfusion of uncrossmatched erythrocytes. Anesthesiology. 2015;122(1):191-5
• (2) Joint United Kingdom (UK) Blood Transfusion and Tissue Transplantation Services Professional Advisory Committee. Handbook of transfusion medicine (2013).
• (3) World Health Organization (WHO). The clinical use of blood - Handbook