Optimization of coagulometric tests that incorporate human plasma for determination of coagulation factor activities in canine plasma

Objective-To optimize methods used to measure coagulation factor activities in canine plasma, define reference ranges in dogs, and compare activities between canine and human plasma. Sample Population-Human plasma samples (n = 5) and plasma from healthy dogs (140) and dogs with low factor V activity (7), high factor V activity (7), and low factor VIII:C activity (6). Procedure-Coagulometric tests incorporated human plasma deficient in a sing le coagulation factor (human deficient plasma). Standard curves were genera ted with pooled plasma from 100 healthy dogs. Effect of sample dilution was evaluated, using plasma from dogs with high or low factor V activity and l ow factor VIII,C activity. Reference ranges for healthy dogs were establish ed. Activities in human plasma were determined by comparison with standard curves obtained with canine plasma, Results-Activities of factors V and VIII:C in samples diluted less than or equal to1:20 influenced results of tests for other coagulation factors. Act ivities of factors V and VIII:C in human plasma were significantly less tha n in canine plasma. For the other coagulation factors, significant differen ces in human plasma-to-canine plasma activity ratios were detected among di fferent sample dilutions. Conclusions and Clinical Relevance-Accurate measurement of coagulation fact or activities in canine plasma, using human deficient plasma, requires high er sample dilutions (ie, > 1:20) than typically used for human plasma. Diff erences in activities between human and canine plasma and nonparallelism of the standard curves emphasize the necessity for use of species-specific st andard curves for accurate determination of coagulation factor activity.