Small Animal Internal Medicine Resident Ontario Veterinary College Guelph, Ontario, Canada
Abstract: Background- Thrombin generation (TG) assessment using Calibrated Automated Thrombogram (CAT) requires a standard volume of plasma (80 uL) and reagent (20 uL) run in triplicate. A low volume CAT method, using half the volume of both plasma and reagent, has been developed in humans and is appealing in veterinary medicine, as it lowers the sampling burden in patients.
Objective- Compare results of CAT in dogs using a standard method and method using low plasma and reagent volumes.
Animals- 30 client-owned dogs with low, normal and high thrombin generation potential recruited from a tertiary referral hospital.
Methods- Blood samples were collected by direct jugular venipuncture in hypocoagulable (n=10), hypercoagulable (n=10) and normal (n=10) dogs. Method comparison was performed between CAT using standard (80 uL plasma, 20 uL reagent- method 1) and low volume (40 uL plasma, 10 uL reagent- method 2) plasma and reagent, respectively. 4 parameters of the TG curve were assessed: lag time (lag); endogenous thrombin potential (ETP); peak; and time to peak (ttpeak).
Results- There was excellent agreement between methods 1 and 2 for all parameters. Lin’s concordance coefficients were 0.97, 0.94, 0.96 and 0.96 for lag time, ETP, ttpeak and peak, respectively. There was a small bias for all parameters (p < .05), resulting in a significant change for lag only. There was a significant predictive linear equation, that when modelled allowed conversion of method 2 to method 1 values.
Conclusion and clinical importance- Low volume CAT is a valid alternative to the standard testing method in dogs.
