Evaluation of a commercially available prothrombin time assay kit for use in dogs and cats

A commercially available assay kit provided a rapid, inexpensive means of evaluating prothrombin time, requiring only 1 drop of fresh blood. We evaluated the assay kit for its ability to accurately measure prothrombin time in dogs and cats, comparing it with a validated prothrombin time assay performed in laboratories. Prothrombin times determined by validated laboratory and assay kit methods were compared, using simple regression analysis. Correlations were high (canine study, r2 = 0.96; feline study, r2 = 0.90; P = 0.0001 in both studies). We concluded that the assay kit compared favorably with the validated laboratory technique. The simplicity and speed with which the test can be performed, accuracy of results, small blood volume required, and cost-effectiveness make the assay kit well suited for prothrombin time measurement by small animal practitioners.