Related Experiment Video
Updated: Aug 3, 2026
Improvement of a Closed Chest Porcine Myocardial Infarction Model by Standardization of Tissue and Blood Sampling Procedures
Published on: March 12, 2018
Evaluation of thromboelastography in two factor XII-deficient cats
Shauna L Blois1, Marie K Holowaychuk1, R Darren Wood1
1Department of Clinical Studies, Ontario Veterinary College, Guelph, ON, Canada.
Insights
Thromboelastography (TEG) in cats with factor XII (FXII) deficiency shows hypocoagulable results with kaolin activation but normal results with tissue factor activation. This finding can help differentiate FXII deficiency from other bleeding disorders.
Area of Science:
- Veterinary Medicine
- Hematology
- Diagnostic Testing
Background:
- Factor XII (FXII) deficiency is the most common inherited hemostatic defect in cats.
- Thromboelastography (TEG) is increasingly utilized for hemostasis evaluation in veterinary patients.
- Previous reports on TEG findings in feline FXII deficiency were lacking.
Observation:
- Two cats, one with perinephric pseudocysts and one healthy, were tested.
- Both cats exhibited prolonged partial thromboplastin times.
- Kaolin-activated TEG tracings were hypocoagulable, while tissue factor-activated TEG tracings were normal to hypercoagulable.
- Subnormal FXII levels were confirmed in both cats.
Findings:
- TEG results in cats with FXII deficiency demonstrate distinct patterns based on the activator used.
- Kaolin activation reflects the intrinsic pathway, which is affected by FXII deficiency.
- Tissue factor activation reflects the extrinsic pathway, which is not directly impacted by FXII deficiency.
Implications:
- Recognizing these TEG patterns is crucial for accurate diagnosis in veterinary patients.
- A hypocoagulable kaolin-activated TEG with a normal tissue factor-activated TEG should prompt consideration of FXII deficiency.
- This can help differentiate FXII deficiency from true hemorrhagic diatheses, avoiding unnecessary treatments.
Case Summary:
The current report describes thromboelastography (TEG) findings in two cats with factor XII (FXII) deficiency. The first cat was diagnosed with bilateral perinephric pseudocysts; hemostatic testing was performed prior to performing renal aspirates. The second cat was healthy; hemostatic testing was performed prior to inclusion into a research project. Both cats had markedly prolonged partial thromboplastin times and hypocoagulable TEG tracings when samples were activated with kaolin. However, when tissue factor (TF) was used to activate the sample, both cats had normal-to-hypercoagulable TEG tracings. The cats each had a subnormal FXII level.
Relevance And Novel Information:
TEG is becoming widely used to investigate hemostasis in veterinary patients, and TEG results in cats with FXII deficiency have not been previously reported. FXII deficiency is the most common hereditary hemostatic defect in cats. While FXII deficiency does not lead to in vivo hemorrhagic tendencies, it can lead to marked prolongation in activated partial thromboplastin and activated clotting times, and cannot be differentiated from true hemorrhagic diatheses without measuring individual factor activity. With the increased use of TEG to evaluate hemostasis in veterinary patients, it is important to recognize the effects of FXII deficiency on this testing modality. The finding of a hypocoagulable kaolin-activated TEG tracing and a concurrent normal TF-activated TEG tracing in samples should prompt clinicians to consider ruling out FXII deficiency.
