The lack of complete knowledge regarding feline red cell antigens, the inability to type beyond the Type AB group, and the proven presence of naturally occurring antibodies to other blood types means that cross-matching is necessary to detect serious antibody-mediated incompatibilities.

Cross-matching is an in vitro test mixing donor and recipient components (blood or plasma) to look for potential incompatibilities manifesting as agglutination or haemolytic reactions.

Major cross-match – assesses compatibility between donor red cells and patient plasma/serum
Minor cross-match – assesses compatibility between patient red cells and donor plasma/serum

In cats, there is differing evidence as to the value of cross-matching the first red cell transfusion. A UK study by Tasker et al (2014) investigated the existence of non–AB blood type incompatibilities and failed to find evidence to support them, as did a later US-based study by Sylvane et al (2018). However, a more recent US study by McClosky et al (2018) reported that 14.9% of transfusion naïve cats had a major cross-match incompatibility. A 2020 Knowledge Summary (Safrany and Adamantos), having evaluated 10 papers, concluded the evidence on this topic to be weak and failed to reach any meaningful clinical conclusion about cross-matching transfusion naïve cats. The summary postulated that the presence of the Mik antigen may be geographical and more prevalent in the USA.

For feline patients, Pet Blood Bank supplies the Woodley RapidVet-H major cross-matching kit. This takes around 20 minutes to perform.

We recommend cross-matching each red cell transfusion in cats, including the first. A minor cross-match is recommended where Type A blood is to be transfused to a Type AB recipient.

In cases where an urgent transfusion is required and you do not have access to an in-house cross-match kit, please download our step by step guide to performing a manual cross-match below.

Cross matching with the Woodley RapidVet-H kit
Step by step guide to manual cross matching