Evaluation of point-of-care versus laboratory antiglobulin-enhanced major crossmatch testing in cats

It is recommended that all cats, regardless of transfusion history, undergo major crossmatch prior to blood product administration to decrease the likelihood of immunological transfusion reactions. A reliable and user-friendly point-of-care crossmatch test would help make crossmatch testing more accessible. The primary objective of this study was to assess agreement between two antiglobulin-enhanced major crossmatch test methods, a laboratory-based tube crossmatch method and a point-of-care gel column crossmatch method, in cats in need of blood transfusion.

Cats that had the potential to require blood transfusion were prospectively recruited. Each cat underwent major crossmatch using two methods concurrently: a laboratory-based tube crossmatch method performed by a reference laboratory, and a gel column crossmatch method performed in the clinic by a clinician and interpreted using guidelines supplied by the manufacturer.

A total of 95 unique donor-recipient pairings were evaluated with both major crossmatch methods. Of the 95 pairings, 21 were incompatible using the laboratory-based tube crossmatch test while 18 were incompatible on the gel column crossmatch test; 13 pairings were incompatible on both methods. Kappa agreement between the laboratory-based tube crossmatch and gel column crossmatch methods was 0.581 (95% confidence interval: 0.378 to 0.785), showing significant agreement. The overall percent agreement between the tests was 86.3%; positive percent agreement was 93.2%, while negative percent agreement was 61.9%.

The commercial antiglobulin-enhanced, point-of-care gel major crossmatch test had moderate agreement with the antiglobulin-enhanced tube crossmatch performed at a reference laboratory. Inclusion of larger numbers of incompatible pairings would help further evaluate the agreement between the two test methods.