Thromboelastography (TEG) provides a global evaluation of hemostasis.1 This diagnostic test is widely used in mammals but has not previously been performed in reptiles, mainly due to the limited availability of class specific reagents. Analysis of the TEG tracing provides identification of hemostatic abnormalities by assessing the speed of clot formation, clot strength, and ultimately fibrinolysis. The objective of this pilot study was to establish a protocol to perform TEG in sea turtles using citrated plasma. Pooled citrated plasma, stored at -80°C, from four green sea turtles (Chelonia mydas) was assayed on a TEG 5000®. Several initiators were evaluated: kaolin (n = 2), Rapid TEG® (n = 2), fresh (n = 2) and frozen (n = 6) thromboplastin extracted from pooled brain tissue from several chelonian species, human recombinant tissue factor at 1:100 (n = 1), reptilase (n = 2), and rabbit thromboplastin (n = 1). Both fresh and frozen thromboplastin were superior to all other reagents, on the basis of obtaining a quantifiable reaction time. Reptilase derived suboptimal tracings, with maximum amplitudes of < 20 mm and, as a result, absent K values. Using all other reagents, there was no reaction time or clot initiation within 90 minutes. These findings are consistent with a lack of an intrinsic pathway in turtles but also confirm a lack of response to mammalian tissue factor. A protocol was subsequently established for the use of harvested thromboplastin with citrated plasma. This will be useful for future studies that aim to understand the pathophysiology of hemostatic disorders in various stranding conditions of sea turtles.
The authors thank Marjory Brooks from the Comparative Coagulation Section, Diagnostic Laboratory, College of Veterinary Medicine, Cornell University, for the brain thromboplastin protocol. In addition the authors thank Joanne Braun McNeill, Larisa Avens, and April Hall for sample collection from free-ranging turtles, Heather Broadhurst, Matthew Godfrey and Sarah Finn for brain tissue. Samples were collected under NMFS ESA scientific research Permit Number 16733, and held and processed under NC WRC Endangered Species Permit 15ST44.
* Presenting author
1. Donahue SM, Otto CM. Thromboelastography: a tool for measuring hypercoagulability, hypocoagulability, and fibrinolysis. Journal of Veterinary Emergency and Critical Care. 2005;15(1):9–16.