An update on blood typing, crossmatching, and doing no harm in transfusing dogs and cats
Let this article help you quickly review blood typing and crossmatching processes so you'll minimize the potential for transfusion reactions. You'll learn about new blood type antigens—Dal in dogs and Mik in cats, and a recently studied extended blood typing kit for dogs.
Figure 1. "Pigtails" from the donor unit may be used to blood type and for crossmatching with the recipient as long as the
unit’s sterility remains intact. (Photo by Charlie Kerlee.)
Freshly collected blood in EDTA and a clot or plain tube from both the recipient and donor are recommended for typing and
crossmatching unless the donor has been screened for antibodies before, in which case only donor cells from the EDTA sample
are needed. Alternatively, tubing segments ("pigtails") (Figure 1) may be used from the donor unit as long as the unit's sterility remains intact. The samples should be free of hemolysis
and lipemia.
Table 1: Selected Blood Typing and Blood Product Websites
Commercial blood typing kits are available for dogs and cats and can be used to screen potential donors and to make appropriate
selections for crossmatches and transfusions based on the recipient's blood type. Examples include typing cards (DMS Laboratories)
and an immunochromatographic cartridge (Alvedia) (Table 1). These kits type for DEA 1.1 only in dogs and for A, B, and AB in cats. Both the cards and cartridge are relatively simple
typing methods, requiring only a few minutes to run, and include a means of performing an auto control to identify potential
interference from autoagglutination. Using a 2+ agglutination endpoint reaction for the cards, one study obtained three false
negative and five false positive reactions out of 88 dog samples tested.15 This issue has reportedly been corrected.16 In the same study, the cartridge obtained no false negative and six false positive results. A gel column diffusion assay
test (DiaMed) used in that study is no longer available for the veterinary market.
Erroneous results can be obtained with failure to follow kit instructions. Autoagglutination and cross contamination from
previously used stir sticks can cause false positive results with card typing methods. False negative results can be obtained
with blood from extremely anemic animals (PCV < 10%) and from a prozone reaction (excess antibody for amount of antigen present).17
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