Initial assessment of a novel gel column coombs’ test to detect auto- and alloantibodies in dogs

The antiglobulin test detects allo- and autoantibodies on the surface of red blood cells or in plasma and has been used in veterinary medicine to detect immune-mediated hemolytic anemia (IMHA) and hemolytic transfusion reactions. In this study, we introduced a novel canine antiglobulin gel column technique for Direct Antiglobulin Testing (DAT) and Indirect Antiglobulin Testing (IAT). DATs and IATs were performed on 115 dogs from 3 groups: non-anemic, healthy dogs (n=30); dogs with suspect IMHA (n=37) and dogs anemic but without suspect IMHA (n=48). On 28 samples (17 suspect IMHA and 11 non-suspect IMHA) the routine tube technique was also performed. For 60 samples the DAT was performed with both unwashed and washed red blood cells. The gel-based DAT was positive in 30/37 (81%) suspect IMHA samples and 2/48 (4%) non-suspect IMHA samples. All healthy dogs and all test controls were negative. If more stringent criteria for inclusion as suspect IMHA were used 30/33 (91%) were positive. When comparing the gel-based and tube DATs, 15/17 (88%) suspect IMHA were positive via the gel-based test whereas 7/17 (41%) were positive via tube. 11/11 (100%) of the non-suspect IMHA group were negative by both methods. There was 97% correlation between DAT results when the test was performed with unwashed and washed red blood cells. Furthermore, saline and antiglobulin gel columns were used to evaluate blood transfusion compatibility (n=147). 4 dogs with a total of 19 crossmatches had incompatibilities discovered solely via the antiglobulin gel column. One dog had induced anti-DEA 1.1 alloantibodies, one dog had induced anti-Dal alloantibodies and 2 dogs had as yet unidentified alloantibodies. Dal-associated incompatibilities are generally recognized with all crossmatch methods. In conclusion, the canine antiglobulin-containing gel columns appear to be a promising, sensitive and specific laboratory technique which can be used as a simple standardized screening tool in identifying dogs with IMHA (DAT, IAT) as well as in determining alloimmune hemolytic transfusion reactions (antiglobulin enhanced crossmatch)