Spherocytes were reported as occasional if they were only seen in some 100 × objective fields. At least 10 high-power fields were evaluated for each count. The direct Coombs' test was performed at 37°C with a combined Coombs' reagent containing goat anticanine immunoglobulin G, immunoglobulin M, and complement C3.g Erythrocytes were washed 4 times before the addition of the Coombs' reagent. Dogs were eligible for inclusion in the study only if their owner gave informed consent.