Comparative Coagulation

The Comparative Coagulation Laboratory provides veterinarians and biomedical researchers comprehensive testing and consultation services for the diagnosis and characterization of blood coagulation disorders in animals. Our laboratory has unique expertise in studying mechanisms of hemostasis and thrombosis and in developing assays to evaluate these systems across species.

Order Comparative Coagulation Tests


We provide veterinarians and biomedical researchers comprehensive testing and consultation services for the diagnosis and characterization of blood coagulation disorders in animals. Our laboratory has unique expertise in studying mechanisms of hemostasis and thrombosis and in developing assays to evaluate these systems in many different species. To fulfill our mission we offer the following:

  • Comprehensive test menu for veterinary clinicians to diagnosis coagulation, platelet, and fibrinolysis defects and tests to monitor anticoagulant therapy.
  • Preclinical testing for drug and device development, including customized test panels and report formats, and GLP compliant studies.
  • Collaborative and translational studies with biomedical and academic researchers.
  • Assistance with study design, test selection, and results interpretation.


Marjory BrooksMarjory Brooks
Director, Comparative Coagulation


The Coagulation Laboratory’s research focuses on the characterization of naturally occurring hemostatic disorders in animals, development of animal models for preclinical testing, and optimization and validation of assays for comparative hemostasis studies.

The Coagulation laboratory actively collaborates with academic and non-academic researchers and test services support contract research and industry scientists. The Laboratory voluntarily participates in the College of American Pathologist’s proficiency testing for coagulation assays and follows the Animal Health Diagnostic Center’s Quality Assurance Program, with accreditation by the AAVLD, and support from the AHDC Quality Assurance Manager to meet documentation needs for GLP compliant studies.

Publications: Research and Collaborations

  • Barratclough A, Conner BJ, Brooks MB, Stablein A, Gerlach TG, Reep RL, Ball RL, Floyd RF. Identifying coagulopathies in the pathophysiology of cold stress syndrome in the Florida manatee (Trichechus manatus latirostris). Diseases of Aquatic Organisms 2017;125:179-188. PubMed PMID: 28792416
  • Ness SL, Frye AH, Divers TJ, Rishniw M, Erb HN, Brooks MB. A Randomized, Placebo-Controlled, Blinded Study of the Effects of Yunnan Baiyao on Parameters of Equine Hemostasis. Am J Vet Res 2017;78:969-976. PubMed PMID: 28738008
  • Brooks MB, Turk JR, Guerrero A, Narayanan PK, Nolan JP, Besteman EG, Wilson DW, Thomas RA, Fishman CE, Thompson KL, Ellinger-Ziegelbauer H, Pierson JB, Paulman A, Chiang AY, Schultze AE. Non-Lethal Endotoxin Injection: A Rat Model of Hypercoagulability. PLoS One. 2017 Jan 12;12(1):e0169976. PubMed PMID: 28081568
  • Stokol T, Scerpa PB, Zahid MN, Brooks MB. Unfractionated and low-molecular-weight heparin and the phosphodiesterase inhibitors, IBMX and cilostazol, block ex vivo Equid Herpesvirus type-1-induced platelet activation. Front Vet Sci 2016;3:99. PubMed PMID: 27909693
  • Hernandez D, Yeo WM, Brooks MB, Ness SL, Divers TJ, Stokol TS. Effect of various anti-platelet drugs on ex vivo Equine Herpesvirus type 1-induced platelet activation. Am J Vet Res 2016;77:1366-1373. PubMed PMID:. 27901390
  • Dixon-Jimenez AC, Brainard BM, Brooks MB, Nie B, Arnold RD, Loper D, Abrams JC, Rapoport GS. Pharmacokinetic and pharmacodynamic evaluation of oral rivaroxaban in healthy adult cats. J Vet Emerg Crit Care 2016;26:619-29. PubMed PMID: 27599304
  • Manion JS, Thomason JM, Langston VC, Claude AK, Brooks MB, Mackin AJ, Lunsford KV. Anticoagulant effects of inhaled unfractionated heparin in the dog as determined by partial thromboplastin time and factor Xa activity. J Vet Emerg Crit Care 2016;26:132-6. PubMed PMID: 26194053
  • Fletcher D, Rozanski L, Delaforcade A, Brainard B, Brooks MB. Assessment of the relationships among coagulopathy, hyperfibrinolysis, plasma lactate, and protein C in dogs with spontaneous hemoperitoneum. J Vet Emerg Crit Care 2016;26:41-51. PubMed PMID: 26220266
  • Frye C, Enders A, Brooks M, Struble AM, Wakshlag J. Assessment of canine platelet-rich plasma produced with a commercial centrifugation and platelet recovery kit. Vet Comp Orthop Traumatol 2016;29:14-19. PubMed PMID: 26194053
  • Brooks MB, Catalfamo JL, MacNguyen R, Tim D, Fancher S, McCardle JA. A TMEM16F point mutation causes an absence of canine platelet TMEM16F and ineffective activation and death-induced phospholipid scrambling. J Thromb Haemost. 2015 Dec;13(12):2240-52. PMID: 26414452
  • Conner B, Hanel R, Brooks MB, Cohn L, Birkenheuer A. Coagulation abnormalities in 5 cats with naturally occurring cytauxzoonosis. J Vet Emerg Crit Care 2015;25:538-545. PMID 2 26082008
  • Aslanian ME, Sharp CR, Rozanski EA, de Laforcade AM, Rishniw M, Brooks MB. Clinical outcome after diagnosis of hemophilia A in dogs. J Am Vet Med Assoc. 2014;245:677-83. PMID 25181272
  • Springer NL, Smith E, Brooks MB, Stokol, T. Flow cytometric detection of circulating platelet-derived microparticles in clinically healthy adult horses. Am J Vet Res 2014;75:879-885. PMID: 25255176
  • Watts AE, Ness SL, Divers TJ, Fubini SL, Frye AH, Stokol T, Cummings KJ, Brooks MB. Effects of clopidogrel on horses with experimentally induced endotoxemia. Am J Vet Res. 2014;75(8):760-9. PMID: 25061708
  • LeVine DN, Birkenheuer AJ, Brooks MB, Nordone SK, Bellinger DA, Jones SL, Fischer TH, Oglesbee SE, Frey K, Brinson NS, Peters AP, Marr HS, Motsinger-Reif A, Gudbrandsdottir S, Bussel JB, Key NS. A novel canine model of immune thrombocytopenia: has immune thrombocytopenia (ITP) gone to the dogs? Br J Haematol. 2014. PMID: 25039744
  • Grochowsky AR, Rozanski EA, de Laforcade AM, Sharp CR, Meola DM, Schavone JJ,  Brooks MB. An ex vivo evaluation of efficacy of refrigerated canine plasma. J Vet Emerg Crit Care  2014;24:388-397. PMID: 25039603 .
  • Brooks MB, Divers TJ, Watts AE, Ness SL, Frye AH, Stokol T, Fubini SL. Effects of clopidogrel on the platelet activation response in horses. Am J Vet Res. 2013  Sep;74(9):1212-22. PMID: 25061708
  • Bebar KN, Sinnott V, Brooks MB. Recurrent hemorrhage caused by type 3 von Willebrand disease in a domestic long-haired cat. J Vet Emerg Crit Care 2014;24(3):326-31. PMID: 24957149.
  • Walton JE, Hale AS, Brooks MB, Boag AK, Barnett W, Dean R. Coagulation factor  and hemostatic protein content of canine plasma after storage of whole blood at ambient temperature. J Vet Intern Med. 2014 Mar;28(2):571-5. PMID: 24467263.
  • Winfield LS, Brooks MB. Hemorrhage and blood loss-induced anemia associated with an acquired coagulation factor VIII inhibitor in a Thoroughbred mare. J Am Vet Med Assoc. 2014 Mar 15;244(6):719-23. PMID: 24568115.
  • Abdelgader AG, Al Momen AKM, Alhaider A, Brooks MB, Catalfamo JL, Al Haidari A, Hussain MF. Anti-haemophilic factor (Factor VIII) and thrombin generation in camel plasma-a comparative studies with humans. Canadian Vet J 2013;77:150-157. PMID: 24082408
  • Pierson JB, Berridge BR, Brooks MB, Kreher K, Koerner J, Schultze AE, Sarazan, RD, Valentin JP, Vargas HM, Pettit SD. A Public-Private Consortium Advances Cardiac Safety Evaluation: Achievements of the HESI Cardiac Safety Technical Committee J Pharmacol Toxicol Methods 2013;68:7-12. PMID: 23567075
  • Helmond SE, Catalfamo JL, Brooks MB. Flow cytometric detection and procoagulant activity of circulating canine platelet-derived microparticles. Am J Vet Res. 2013 Feb;74(2):207-15. PMID: 23363344
  • Mayhew PM, Savigny MR, Otto CM, Brown DC, Brooks MB, Bentley AM, Runge JF, Callan MB. Evaluation of coagulation in dogs with partial or complete extra-hepatic biliary tract obstruction using thromboelastography. J Am Vet  Med Assoc. 2013 Mar 15;242(6):778-85. PMID 23445288
  • Schultze AE, Walker DB, Turk JR, Tarrant JM, Brooks MB, Pettit SD. Current practices in preclinical drug development: gaps in hemostasis testing to assess risk of thromboembolic injury. Toxicol Pathol. 2012 Toxicol Pathol. 2013;41(3):445-53. PMID 22991386
  • Jandrey KE, Norris JW, Tucker M, Brooks MB. Clinical characterization of canine platelet procoagulant deficiency (Scott Syndrome). J Vet Intern Med. 2012  Nov-Dec;26(6):1402-7. PMID 23061683
  • Donahue, SM, Brooks M, Otto CM. Examination of hemostatic parameters to detect hypercoagulability in dogs with severe protein-losing nephropathy. J Vet Emerg Crit Care (San Antonio). 2011 Aug;21(4):346-55. doi: 10.1111/j.1476-4431.2011.00656.x. PMID 21827592
  • Watts AE, Fubini SL, Todhunter RJ, Brooks MB. Comparison of plasma and peritoneal indices of fibrinolysis between foals and adult horses with and without colic. Am J Vet Res. 2011 Nov;72(11):1535-40. PMID 22023133
  • Sharpe KS, Center SA, Randolph JF, Brooks MB, Warner KL, Stokol T, Barr, SC, Felippe MJ. Influence of treatment with ultralow-dose aspirin on platelet aggregation as measured by whole blood impedence aggregometry and platelet P-selectin expression in clinically normal dogs. Am J Vet Res. 2010 Nov;71(11):1294-1304. PMID 21034320
  • Booth CJ, Brooks MB, Rockwell S, Murphy JW, Rinder HM, Zelterman D, Paidas MJ, Compton SR, Marks PW. WAG-F8(m1Ycb) rats harboring a factor VIII gene mutation provide a new animal model for hemophilia A. J Thromb Haemost. 2010 Nov;8(11):2472-77. doi: 10.1111/j.1538-7836.2010.03978.x. PMID 20626616
  • Yaxley PE, Beal MW, Jutkowitz LA, Hauptman JG, Brooks MB, Hale AS, Parr A. Comparative stability of canine and feline hemostatic proteins in freeze-thaw-cycled fresh frozen plasma. J Vet Emerg Crit Care (San Antonio). 2010 Oct;20(5):472-78. doi: 10.1111/j.1476-4431.2010.00563.x. PMID 20955297
  • Booth CJ, Brooks MB, Rockwell S. Spontaneous coagulopathy in inbred WAG/RijYcb rats. Comp Med. 2010 Feb;60(1):25-30. PMID 20158945
  • Brooks M, Etter K, Catalfamo J, Brisbin A, Bustamante C, Mezey J. A genome-wide linkage scan in German shepherd dogs localizes canine platelet procoagulant deficiency (Scott syndrome) to canine chromosome 27. Gene. 2010 Jan 15;450(1-2):70-5. PMID 19854246

Publications: Test Services

  • Culler CA, Iazbik C, Guillaumin J. Comparison of albumin, colloid osmotic pressure, von Willebrand factor, and coagulation factors in canine cryopoor plasma, cryoprecipitate, and fresh frozen plasma. J Vet Emerg Crit Care (San Antonio). 2017 Nov;27(6):638-644. PubMed PMID: 29035661
  • Keeshen TP, Case JB, Runge JJ, Singh A, Mayhew PD, Steffey MA, Culp WTN. Outcome of laparoscopic ovariohysterectomy or ovariectomy in dogs with von Willebrand disease or factor VII deficiency: 20 cases (2012-2014). J Am Vet Med Assoc. 2017 Nov 1;251(9):1053-1058. PubMed PMID: 29035661
  • Barratclough A, Ball RL, Floyd RF, Reep RL, Conner BJ. Proposal and application of a novel disseminated intravascular coagulation scoring system in the Florida Manatee (Trichechus manatus latirostris). J Zoo Wildl Med. 2017 Mar;48(1):152-158. PubMed PMID: 28363081
  • Flores RS, Boudreaux MK, Vasquez B, Bristow P, Aronson LR, Santoro-Beer K, Callan MB. Heterozygosity for P2Y12 receptor gene mutation associated with postoperative hemorrhage in a Greater Swiss Mountain dog. Vet Clin Pathol. 2017. PMID:28800150
  • Kaye S, Abou-Madi N, Fletcher DJ. Effect of ε-Aminocaproic acid on fibrinolysis in plasma of Asian elephants (ELEPHAS MAXIMUS). J Zoo Wildl Med. 2016 Jun;47(2):397-404. PMID: 27468009
  • White CR, Langston C, Hohenhaus AE, Lamb K, Hackner S, Fox PR. Evaluation of the relationship between clinical variables and thromboelastographic findings in dogs with protein-losing nephropathy. J Vet Emerg Crit Care (San Antonio). 2016 Jan;26(1):74-9. PMID: 26458243
  • Gerlach TJ, Bandt C, Conner B, Ball RL. Establishment of reference values for  various coagulation tests in healthy Florida manatees (Trichechus manatus latirostris) and evaluation of coagulation in debilitated manatees during rehabilitation. J Am Vet Med Assoc. 2015 Nov 1;247(9):1048-55. PMID: 26480015
  • Adamantos S, Waters S, Boag A. Coagulation status in dogs with naturally occurring Angiostrongylus vasorum infection. J Small Anim Pract. 2015 Aug;56(8):485-90. PMID: 26032443
  • Pashmakova MB, Barr JW, Bishop MA. Stability of hemostatic proteins in canine fresh-frozen plasma thawed with a modified commercial microwave warmer or warm water bath. Am J Vet Res. 2015 May;76(5):420-5. PMID 25909374
  • Fletcher DJ, Blackstock KJ, Epstein K, Brainard BM. Evaluation of tranexamic acid and ϵ-aminocaproic acid concentrations required to inhibit fibrinolysis in plasma of dogs and humans. Am J Vet Res. 2014 Aug;75(8):731-8. PMID 25061704
  • Holowaychuk MK, Hanel RM, Wood RD, Rogers L, O’Keefe K, Monteith G. Prospective multicenter evaluation of coagulation abnormalities in dogs following severe acute trauma. J Vet Emerg Crit Care (San Antonio). 2014 Jan-Feb;24(1):93-104. doi: 10.1111/vec.12141. PMID 24410816
  • Epstein KL, Bergren A, Giguère S, Brainard BM. Cardiovascular, colloid osmotic pressure, and hemostatic effects of 2 formulations of hydroxyethyl starch in healthy horses. J Vet Intern Med. 2014 Jan-Feb;28(1):223-33. PubMed. PMID: 24428324
  • Kelley D, Lester C, Delaforcade A, Webster CR. Thromboelastographic evaluation of dogs with congenital portosystemic shunts. J Vet Intern Med. 2013 Sep;27(5):1262-7. PMID: 23815243
  • Fletcher DJ, Brainard BM, Epstein K, Radcliffe R, Divers T. Therapeutic plasma concentrations of epsilon aminocaproic acid and tranexamic acid in horses. J Vet  Intern Med. 2013 Nov-Dec;27(6):1589-95. PMID 24118238
  • Pace SL, Creevy KE, Krimer PM, Brainard BM. Assessment of coagulation and potential biochemical markers for hypercoagulability in canine hyperadrenocorticism. J Vet Intern Med. 2013 Sep;27(5):1113-20. PMID: 23952553
  • Urban R, Guillermo Couto C, Cristina Iazbik M. Evaluation of hemostatic activity of canine frozen plasma for transfusion by thromboelastography. J Vet Intern Med. 2013 Jul;27(4):964-9. PMID: 23663247
  • Lennon EM, Hanel RM, Walker JM, Vaden SL. Hypercoagulability in dogs with protein-losing nephropathy as assessed by thromboelastography. J Vet Intern Med.  2013 May;27(3):462-8. PMID: 23528002
  • Blong AE, Epstein KL, Brainard BM. In vitro effects of three formulations of hydroxyethyl starch solutions on coagulation and platelet function in horses. Am  J Vet Res. 2013 May;74(5):712-20. PMID: 23627384
  • Bentley AM, Mayhew PD, Culp WT, Otto CM. Alterations in the hemostatic profiles of dogs with naturally occurring septic peritonitis. J Vet Emerg Crit Care (San Antonio). 2013 Jan;23(1):14-22. doi: 10.1111/vec.1 2013. Epub 2013 Jan 14. PubMed. PMID: 23317011
  • Babski DM, Brainard BM, Ralph AG, Pittman JR, Koenig A. Sonoclot® evaluation of single- and multiple-dose subcutaneous unfractionated heparin therapy in healthy adult dogs. J Vet Intern Med. 2012 May-June;26(3):631-38. doi: 10.1111/j.1939-1676.2012.00907.x. PMID 22435404
  • Fiakpui NN, Hogan DF, Whittem T, Green HW 3rd, Shipley EQ, Sederquist KA. Dose determination of fondaparinux in healthy cats. Am J Vet Res. 2012 Apr;73(4):556-61. doi: 10.2460/ajvr.73.4.556. PMID 22452504
  • Vilar Saavedra P, Lara García A, Zaldívar López S, Couto G. Hemostatic abnormalities in dogs with carcinoma: a thromboelastographic characterization of hypercoagulability. Vet J. 2011 Nov;190(2):e78-83. PMID 21454111
  • Dawson DR, DeFrancisco RJ, Stokol T. Reference intervals for hematologic and coagulation tests in adult alpacas (Vicugna pacos). Vet Clin Pathol. 2011 Dec;40(4):504-12. doi: 10.1111/j.1939-165X.2011.00359.x. PMID 22092869
  • Van De Wiele CM, Hogan DF, Green HW 3rd, Sederquist KD. Antithrombotic effect of enoxaparin in clinically healthy cats: a venous stasis model. J Vet Intern Med. 2010 Jan-Feb; 24(1):185-91. PMID 19912519
  • Rattner BA, Horak KE, Warner SE, Johnston JJ. Acute toxicity of diphacinone in Northern bobwhite: effects on survival and blood clotting. Ecotoxicol Environ Saf. 2010 Sep;73(6):1159-64. PMID 20580432
  • McLean NS, Ward DA, Hendrix DV, Donnell RL, Ilha MR. Ligneous conjunctivitis secondary to congenital plasminogen deficiency in a dog. J Am Vet Med Assoc. 2008 Mar 1;232(5):715-21. PMID 18312178
  • Scott KC, Hansen BD, DeFrancesco TC. Coagulation effects of low molecular weight heparin compared with heparin in dogs considered to be at risk for clinically significant venous thrombosis. J Vet Emerg Crit Care (San Antonio). 2009 Feb;19(1):74-80. PMID: 19691587.