Packed RBC (pRBC) transfusions are common in small animals in the intensive care unit. Debate exists on how long to wait before PCV should be rechecked after transfusion. This prospective study sampled PCV measurements taken before and after pRBC transfusions in 46 (n = 50) pet dogs. Posttreatment PCV measurements were taken at 0 minutes, 30 minutes, 1 hour, 2 hours, and 4 hours. Mean pretransfusion PCV was 0.15 L/L (15%). Mean posttransfusion PCV was 0.28 L/L (28%) at 0 minutes and 0.27 L/L (27%) at all other time points. Crucially, PCV did not change significantly over all posttransfusion time points, and there was no significant difference among any of the time points, regardless of whether anemia was regenerative or nonregenerative or if there was ongoing RBC loss or destruction. The authors concluded that rechecking PCV immediately after transfusion is as reliable as waiting up to 4 hours.