Activated partial thromboplastin time as a screening test of minor or moderate coagulation factor deficiencies for canine plasma: sensitivity of different commercial reagents

To determine the sensitivity for detection of coagulation factor deficienci es by commercial reagents for canine plasma, 5 commercial activated partial thromboplastin time (APTT) reagents with different types of contact activa tor and phospholipid of various origin were examined. Thirty canine plasma samples with minor or moderate deficiencies of coagualition factors that in fluence the APTT were examined. Significant differences were found for the sensitivity of various reagents, but no correlation was found with the type of contact activator. Following the test instructions provided by the manu facturers, the number of APTT results that were prolonged beyond the refere nce range varied between 20 and 30 (sensitivity = 0.67-1.00); the number of corresponding results using a standardized test protocol varied between 19 and 28 (sensitivity: 0.63-0.93). The most sensitive reagent contained kaol in as a contact activator and a human placental thromboplastin. The results of this study indicate that the APTT test optimized for human plasma is al so a sensitive screening test of the intrinsic system of canine plasma, pro vided that a suitable reagent is used.