Good agreement of conventional and gel-based direct agglutination test in immune-mediated haemolytic anaemia

BACKGROUND: The aim of this study was to compare a gel-based test with the traditional direct agglutination test (DAT) for the diagnosis of immune-mediated haemolytic anaemia (IMHA). METHODS: Canine (n = 247) and feline (n = 74) blood samples were submitted for DAT testing to two laboratories. A subset of canine samples was categorized as having idiopathic IMHA, secondary IMHA, or no IMHA. RESULTS: The kappa values for agreement between the tests were in one laboratory 0.86 for canine and 0.58 for feline samples, and in the other 0.48 for canine samples. The lower agreement in the second laboratory was caused by a high number of positive canine DATs for which the gel test was negative. This group included significantly more dogs with secondary IMHA. CONCLUSIONS: The gel test might be used as a screening test for idiopathic IMHA and is less often positive in secondary IMHA than the DAT.