Component compatibility

Patients should receive ABO-identical blood products whenever possible, however sometimes it may be necessary to provide ABO-compatible blood products instead.

The table below lists the acceptable blood group choices in order of preference.

Red cells

Pretransfusion testing is required to identify compatible red cells. Consult your Transfusion Service Provider about your requirements for samples and request forms.

Patient unknown ABO and RhD type	Emergency use	Never use
Female ≤ 50 years or Male ≤ 18 years	O RhD negative#	A, B, AB
Female > 50 years or Male > 18 years	O RhD positive or O RhD negative	A, B, AB

# O RhD positive red cells should never be withheld for life-saving transfusion.

Patient ABO type	Best option	OK to use	Never use
O	O	-	A, B, AB
A	A	O	B, AB
B	B	O	A, AB
AB	AB	O, A, B	-

Patient RhD type	Best option	OK to use	Warning*
RhD negative	RhD negative	-	RhD positive*
RhD positive	RhD positive	RhD negative	-

* RhD negative males (>18 years) and females not of childbearing potential (> 50 years) may safely be given RhD positive red cells but have a risk of developing anti-D antibodies.

The following patient groups should receive RhD negative red cells:

RhD negative patients with anti-D
RhD negative females of childbearing potential
Females of childbearing potential with unknown blood group (in an emergency)
RhD negative paediatric males, and
RhD negative patients who will receive repeated transfusions or are likely to become transfusion dependent.

Some regional and smaller metropolitan hospitals may only hold O RhD positive red cells for emergency use (e.g. in life-threatening situations).

Kell blood group system compatibility

Kell blood group system antibodies should be considered clinically significant and are known to cause both transfusion reactions and haemolytic disease of the fetus and newborn (HDFN). 

The Australian and New Zealand Society of Blood Transfusion (ANZSBT) and Lifeblood released a joint Consensus statement on use and allocation of Kell negative red cells to assist in the equitable and appropriate availability of K negative red cells.

Clinical scenarios where K negative red cells are indicated (listed in priority order) include:

Any patient with (or a history of) anti-K.

Transfusion of pregnant females or females of childbearing potential (≤ 50 years) who are K negative (∼90% of women).
Transfusion of pregnant females or females of childbearing potential who are unable to be phenotyped prior to transfusion. The clinical urgency of transfusion should be considered, and emergency transfusion should not be delayed by attempts to source K negative units.
Patients receiving daratumumab (anti-CD38 monoclonal antibody) therapy who are K negative or whose K phenotype (or genotype) cannot be determined
Transfusion dependent patients who are shown to be K negative (∼90% of patients). However, laboratories may choose the option of transfusing K negative units only if the patient subsequently develops anti-K.

Platelets

Patient ABO type	Best option	OK to use	Avoid if possible
Unknown	O or A RhD negative	-	B, AB
O	O	A	B, AB
A	A	B, O	AB
B	B	A, O	AB
AB	AB (not routinely available)	A, B	O

Note:

Group A platelets with the A2 subgroup have decreased expression of A antigen and are therefore preferable to other group A platelets when transfusing group O and B recipients.
Apheresis platelets that have a low titre anti-A+B antibody or pooled platelets pose a lower risk of haemolysis when transfusing ABO incompatible components.

Platelets with the same RhD type as the recipient are the ideal option. If RhD positive platelets are given to an RhD negative female of childbearing potential, then RhD immunoglobulin (RhD-Ig) should be given.

If it’s necessary to provide platelets with a blood group other than the patient’s own, the clinical circumstances, specific component availability (pooled vs apheresis) and a requirement for special components (e.g. HLA or HPA matched), may influence the decision to give platelets that are incompatible for either ABO and/or RhD antigens or ABO antibodies.

If an ABO antigen compatible/antibody incompatible platelet transfusion is given (e.g. group A patient receiving group O platelets), the patient may develop haemolysis and a positive direct antiglobulin test (DAT). This is of greater importance in children as they have lower levels of soluble A and B substance in their body fluids which would otherwise contribute to neutralising the transfused ABO antibodies.

If an ABO and/or RhD antigen incompatible/antibody compatible platelet transfusion is given (e.g. group O RhD negative patient receiving A RhD positive platelets), the post-transfusion platelet increment (PPI) and platelet survival may be lower than expected. Sensitisation to RhD may occur due to residual RhD positive red cells in the platelet component.

Prophylactic RhD immunoglobulin may be indicated when RhD positive platelets are transfused to an RhD negative patient, particularly females of childbearing potential.

Plasma

Patient ABO blood type	Best option	OK to use	Warning*
Unknown	AB	A^#	B
O	O	A, B, AB	-
A	A	AB	B
B	B	AB	A
AB	AB	-	A, B

* Always check with the lab before administering. # Group A plasma may be used as per local institutional policies.

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 that have a low titre anti-A+B antibody pose a lower risk of haemolysis when transfusing ABO incompatible components.

If an ABO incompatible plasma transfusion is given (e.g. group A patient receiving group O platelets), the patient may develop haemolysis and a positive direct antiglobulin test (DAT). This is of greater importance in children as they have lower levels of soluble A and B substance in their plasma.

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.