Establishment of a reference interval for a novel viscoelastic coagulometer and comparison with thromboelastography in healthy cats

Abstract

BackgroundViscoelastic analysis provides information on the dynamics and strength of clot formation as well as clot stability. A novel point‐of‐care viscoelastic test (Viscoelastic Coagulation Monitor Vet, VCM Vet) could be more cost‐effective, simpler to use, and more portable than thromboelastography (TEG).ObjectivesThe primary aim of this study was to establish a feline reference interval (RI) for the VCM Vet. A secondary aim was to compare VCM Vet analysis with TEG in healthy cats.MethodsFifty‐six healthy cats were enrolled in this study. Linear regression was completed to determine whether age and CBC parameters were associated with the VCM Vet parameters and if TEG parameters were correlated with VCM Vet data. Statistical significance was set at P < .05.ResultsFifty‐three VCM Vet tracings were used to determine RIs for healthy cats. The determined RIs were: clot time (CT) 104‐438 seconds; clot formation time (CFT) 104.5‐488 seconds; alpha angle (AA) 30.5°‐70°; a10 13.8‐32.7 VCM units; a20 19.2‐40.1 VCM units; maximum clot formation (MCF) 22.5‐44.8 VCM units; Lysis Index 30 (Li30) 92.9%‐100.9%; and Lysis Index 45 (Li45) 92%‐100%. Linear regression identified a strong positive correlation between the CT and R‐time measured using the VCM Vet and TEG methods, respectively; no other parameters were correlated.ConclusionsThe use of VCM Vet is feasible in cats, and we determined the first described feline RIs for this test. In general, the VCM Vet data did not correlate with TEG in healthy cats.

Viscoelastic Coagulation Monitor (VCM^Vet) Reference Intervals and Sex Differences in Mature Adult Mice

“…In the present study, CT trended shorter in male versus female mice; however, we found no significant difference between male and female mouse CT values. This is consistent with the results of a recent VCM study of male and female cats [7] and comparable with TEG R values in female versus male adult human patients [5]. Interestingly, a study by Kopic et al [16] reported significantly shorter TEG R values in male versus female juvenile C57BL/6N mice, though sample sizes and reported differences were small; most strains of juvenile mice in the Kopic study showed no significant differences between male and female mean TEG R values, which is more consistent with our observations of adult mice in the present study.…”

“…To our knowledge, this study is the first to demonstrate use of VCM Vet TM to analyze blood coagulation properties in mice. To date, other investigators have published studies using VCM Vet TM to analyze blood from cats [7, 8], dogs [14], and bats [10]. In this study, we determined VCM Vet TM RIs for healthy mature adult C57BL/6N mice and reference value ranges needed for blood coagulation testing in experimental and preclinical studies with mice.…”

“…VCM Vet TM trace data are similar to thromboelastography (TEG) or rotational thromboelastography (ROTEM) and can be interpreted qualitatively as such. A recent study of felines comparing VCM Vet TM and TEG [7] found significant positive correlation between VCM Vet TM values for CT and MCF and TEG values for R (time to initial clotting reaction) and MA (maximal amplitude, i.e., clot firmness), respectively. Notably in the feline study, no other significant correlations were found between other VCM and TEG parameters.…”

“…For each VCM parameter, RIs (central 95% of reference values with 90% upper and lower confidence intervals [CIs]) were determined as recommended by the American Society for Veterinary Clinical Pathology (ASVCP) [9] and as described by other investigators [7, 10], using Reference Value Advisor v2.1 macro for Microsoft Excel (Microsoft Corp., Redmond, WA, USA) [11]. Probable outliers were identified by visually examining histograms and using Grubb’s test (alpha = 0.05).…”

“…The Viscoelastic Coagulation Monitor (VCM Vet TM ; Entegrion Corp.) is a relatively new coagulometer designed specifically for veterinary clinical use that is shown to yield values similar to TEG or ROTEM [1, 7, 8]. The VCM Vet TM instrument is much smaller than other devices, as well as cordless and portable, which is convenient for quickly analyzing fresh whole blood immediately after sampling.…”