ORIGINAL ARTICLESClot formation in canine whole blood as measured by rotational thromboelastometry is influenced by sample handling and coagulation activatorSmith, Stephanie Aa; McMichael, Maureenb; Galligan, Alyssab; Gilor, Shirb; Hoh, Crystal MbAuthor Information aDepartment of Biochemistry, College of Medicine, USA bDepartment of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Illinois, USA Received 7 April, 2010 Revised 6 July, 2010 Accepted 22 July, 2010 Correspondence to Stephanie A. Smith, DVM, MS, MSB Room #461, 506 S. Mathews, MC-714, Urbana, IL 61801, USA Tel: +1 217 265 5424; fax: +1 217 265 5290; e-mail: [email protected] Blood Coagulation & Fibrinolysis: October 2010 - Volume 21 - Issue 7 - p 692-702 doi: 10.1097/MBC.0b013e32833e9c47 Buy Metrics Abstract The objective of the present study was to systematically evaluate the impact of methodology on thromboelastometry with canine whole blood. Thromboelastometry was performed on citrated blood using a variety of combinations of clotting activators [ex-tem (tissue factor or TF), in-tem (ellagic acid), diluted TF from Innovin, or Ca (recalcification only)] and storage times. Thromboelastometry was also performed using diluted TF from Innovin on blood collected into a contact inhibitor. Ex-vivo contact activation was compared between canine and human blood. Clotting activator had a marked impact on coagulation time, a minor impact on alpha angle, and no impact on clot formation time or maximum clot firmness. When ex-tem or in-tem was the clotting activator, sample storage up to 30 min did not affect results. With diluted TF from Innovin or Ca, sample storage was associated with the development of increased coagulability (as indicated by shorter coagulation time and clot formation time and higher alpha angle) due to ex-vivo contact activation. Canine blood underwent markedly more ex-vivo contact activation than did human blood. Canine blood undergoes significant ex-vivo contact activation during and after collection, which influences thromboelastometry results when a weak clotting activator (such as low TF or recalcification) is used. Thromboelastometry with a strong activator (such as ex-tem or in-tem) is less influenced by ex-vivo changes, and, therefore, likely to be more reflective of in-vivo hemostatic capabilities and to provide consistently interpretable and comparable results. © 2010 Lippincott Williams & Wilkins, Inc.