Component compatibility

Whenever possibe, patients should receive ABO-identical blood products, however on occasions it may be necessary to provide ABO-compatible blood products instead. The table below lists the acceptable blood group choices in order of preference.

ABO component compatibility table

  Red cells Platelets Plasma components
Unknown patient O# A or O (low titre anti-A/B) AB*
  Red cells Platelets Plasma components
First choice O O O
Second choice   A** A or B
Third choice   AB AB
  Red cells Platelets Plasma components
First choice A A A
Second choice O O (low titre anti-A/B) AB
Third choice   AB or B, O  
  Red cells Platelets Plasma components
First choice B B B
Second choice O O (low titre anti-A/B) AB
Third choice   AB or A, O  
  Red cells Platelets Plasma components
First choice AB AB AB
Second choice A or B O (low titre anti-A/B) A*
Third choice O A or B, O  

#  If patient is a female of child bearing potential, O RhD negative red cells should be used until patient’s blood group is established.
* Group A plasma may be used as per local institutional policies.
** Group A platelets that have an A2 subgroup do not express significant amounts of A antigen and are, therefore, compatible with group O recipients.


Clinical information

You should always refer to your local hospital policies and seek advice from a Consultant Haematologist, your local laboratory service provider, a Blood Service Transfusion Medicine Specialist or Scientist when transfusion of components other than the patient’s own blood group is necessary, especially in emergency situations or when stocks are limited or unavailable.
Incompatible transfusions can result in serious harm to or death of the recipient.

Red cell compatibility

Pretransfusion testing is required for the release of compatible red cells. Consult your laboratory service provider about your requirements for samples and request forms.

Group RhD negative red cells can be transfused to RhD positive recipients safely, however transfusing RhD negative recipients with RhD positive red cells can result in the formation of anti-D.

The following patient groups should receive RhD negative red cells:

  • group O RhD negative patients with anti-D
  • group O RhD negative females of child-bearing potential
  • females of child-bearing potential with unknown blood group (in an emergency)
  • group O RhD negative children (males and females <16 years)
  • group O RhD negative patients who will receive repeated transfusions, or are likely to become transfusion-dependent

Of note, some regional and smaller metropolitan hospitals may only hold Group O RhD positive red cells for emergency use only (eg, in life threatening situations).

The Kell blood group system contains antigens that are highly immunogenic and are considered clinically significant. They have been known to cause both haemolytic transfusion reactions and haemolytic disease of the newborn.  The Australian and New Zealand Society of Blood Transfusion and the Australian Red Cross Blood Service have developed a Consensus statement on use and allocation of Kell negative red cells. The following recommendations have been made:

  1. Clinical scenarios where K negative red cells are indicated (listed in priority order) include:
    • Any patient with (or a history of producing) anti-K
    • Elective transfusion of pregnant females or females of child bearing potential who have a K negative phenotype (∼90% of women)
    • Transfusion of pregnant females or females of child bearing potential who are unable to be phenotyped prior to transfusion, where possible. The clinical urgency of transfusion should be considered and emergency transfusion should not be delayed by attempts to source K negative units.
  2. K negative units may be clinically indicated in the following scenario:
    • Patients commenced on, or likely to be commenced on, a recurrent transfusion program who are shown to have a K negative phenotype (∼90% of patients). Laboratories may choose to phenotype but may elect to retain the option of transfusing K negative units only if the patient subsequently develops anti-K.


Platelet compatibility

If it is necessary to provide platelets other than the patient’s own blood group, the patient’s age, diagnosis, therapy, component type availability (ie apheresis platelets vs pooled platelets) as well as any special circumstances (eg HLA matched) may influence the decision to give either antigen-incompatible or antibody-incompatible platelets.

If an ABO antigen compatible/plasma incompatible platelet transfusion (eg group A patient given group O platelets) is given, the recipient may develop a positive direct antiglobulin test (DAT) which may result in haemolysis. This is of greater importance in children as they have lower levels of soluble A and B substance in their body fluids.

If an ABO and/or RhD antigen incompatible/plasma compatible platelet transfusion (eg group O RhD negative patient given A RhD positive platelets) is given the post-transfusion platelet increment and platelet survival may be lower in some patients. Sensitisation to foreign red cell antigens and in particular RhD may also occur.

Prophylactic RhD immunoglobulin may be indicated when RhD positive platelets are transfused to an RhD negative recipient, particularly in female children or women of childbearing age. Contact your transfusion service provider or Haematologist for further advice.

Plasma compatibility

Plasma components (e.g. fresh frozen plasma, cryoprecipitate and cryodepleted plasma) should be compatible with the ABO group of the recipient to avoid potential haemolysis caused by donor anti-A or anti-B. Plasma components of any RhD type can be given regardless to the RhD type of the recipient. RhD immunoglobulin is not required in these situations.