Activated coagulation times of whole blood in normal dogs and dogs with coagulopathies

The activated coagulation time (ACT) of whole blood was determined at 37C and at room temperature for 42 normal dogs and eight dogs with naturally–occurring or experimentally–induced coagulation defects.
Normal ACT values ranged from 64 to 95 seconds at 37C, and 83 to 129 seconds at room temperature. In abnormal dogs, ACT was increased on 14 of 17 occasions that a prolonged activated partial thromboplastin time (APTT) was recorded: the ACT failed to detect an abnormality on three occasions the APTT was slightly increased. ACT determination at 37C correlated better with APTT than did ACT testing at room temperature.
The ACT test is simple, inexpensive and convenient. It is a useful screening test for intrinsic coagulation defects in the dog. It is suggested that the test be performed at 37C: at this temperature an ACT of 95 seconds or more in a dog warrants further investigation.