Comparison of five blood-typing methods for the feline AB blood group system

Abstract

Objective-To compare the ease of use and accuracy of 5 feline AB blood-typing methods: card agglutination (CARD), immunochromatographic cartridge (CHROM), gel-based (GEL), and conventional slide (SLIDE) and tube (TUBE) agglutination assays. Sample Population-490 anticoagulated blood samples from sick and healthy cats submitted to the Transfusion or Clinical Laboratory at the Veterinary Hospital of the University of Pennsylvania. Procedures-Sample selection was purposely biased toward those from anemic, type B, or type AB cats or those with autoagglutination. All blood samples were tested by use of GEL, SLIDE, and TUBE methods. Fifty-eight samples were also tested by use of CARD and CHROM methods. The presence of alloantibodies in all cats expressing the B antigen as detected by use of any method was also assessed. Results-Compared with the historical gold-standard TUBE method, good to excellent agreement was achieved with the other typing tests: CARD, 53 of 58 (91% agreement); CHROM, 55 of 58 (95%); GEL, 487 of 490 (99%); and SLIDE, 482 of 487 (99%; 3 samples were excluded because of autoagglutination). Four of the samples with discordant test results originated from cats with FeLV-related anemia. Conclusions and Clinical Relevance-Current laboratory and in-clinic methods provide simple and accurate typing for the feline AB blood group system with few discrepancies. Retyping after in-clinic typing with the GEL or TUBE laboratory methods is recommended to confirm any type B or AB cats.

Figure 1

Photographs of results of GEL, CARD, and CHROM blood-typing methods for a type A cat with FeLV-related anemia and from a healthy type AB cat. Notice that the B antigen reaction is positive in the FeLV-positive cat but is weaker than in the healthy type AB cat. In 1 sample from a cat with FeLV-related anemia, the GEL test reaction shows a split population of RBCs in the anti-B column, making the results inconclusive. Also notice that for the CARD test, the anti-B reaction is stronger than the anti-A reaction for the healthy type AB cat.