Determination of normal values using an automated coagulation timer for activated coagulation time and its application in dogs with hemophilia

The present study was performed to determine normal values for the Medtroni c HemoTec automated activated coagulation time (ACT) analyzer (Medtronic He moTec Inc, Parker, CO, distributed in Switzerland by Convergenza AG, Vaduz, Liechtenstein), and to evaluate its ability to detect dogs with hemophilia . ACT was measured in 43 healthy dogs presented to the Companion Animal Hos pital, University of Bern, Bern, Switzerland, with the Medtronic HemoTec AC T analyzer to determine normal values. The mean +/- 2 standard deviations ( SDs) of the values obtained was defined as the normal range. ACT was measur ed 8-10 times on the same day in 6 dogs to determine repeatability. ACT als o was measured in 11 dogs with hemophilia and compared with a conventional visual ACT measurement test and with the activated partial thromboplastin t ime (APTT). ACT values of the 43 dogs used to determine normal values range d from 66.5 to 97.0 seconds (mean, 79.3 seconds; SD, 7.35 seconds; median, 78.5 seconds). A range of 64-95 seconds (mean +/- 2 SDs) was defined as the normal range for the tested device. Repeatability was poor (r = 0.256). AC T values measured with the automated device did not correlate with ACT valu es measured with a conventional visual rest or with APTT. Sensitivity of th e test was 90.9%, specificity was 98.0%, and accuracy was 96.7%. Variabilit y in the test results was large and may lead to incorrect results. The auto mated measurement device was not superior to the conventional visual method in evaluating dogs with hemophilia.