Metabolomic peritoneal fluid profile in horses with ischaemic and obstructive intestinal disease: Preliminary results of an ongoing prospective study

Background: The Wellness Ready Test (WRT) 1 is a stable-side lateralflow test for measuring blood insulin concentrations in equids.The assay has been validated and compared with a radioimmunoassay used commercially in the USA.A method comparison with insulin assays commonly used in the UK has not been reported and would facilitate clinical application of the WRT.Objectives: To compare the results of WRT insulin analysis with the Immulite chemiluminescent immunoassay (ICLIA) 2 and the Tosoh immunofluorescent assay (TIFA) 3 . Study design: Method comparison.Methods: Insulin concentrations were analysed from clinical cases for routine diagnosis (ICLIA).Residual blood was used for comparative analysis using the WRT and TIFA.To account for the WRT's restricted range (20-99.9IU/mL), data were reformatted, with ICLIA and TIFA values restricted to the same range.Continuous data were analysed using Lin's concordance correlation coefficients (CCC), Pearson's r values and Bland-Altman plots.Clinically relevant WRT cut-offs for laminitis risk were derived by ROC analysis compared with the reference method (TIFA).Continuous insulin data were categorised using method-specific laminitis risk cut-offs.Cohen's kappa coefficient is reported for inter-method agreement of categorical insulin data.Results: 59 samples were analysed.Concordance between testing methods was strong; WRT/ICLIA CCC 0.84 (95% CI 0.76-0.91),Pearson's r 0.85, p <0.001; WRT/TIFA CCC 0.90 (95% CI 0.86-0.95),Pearson's r 0.93, p <0.001.Derived cut-offs for WRT insulin values were low risk <22.2 IU/mL, high risk >48.3 IU/mL.Cohen's kappa coefficient for laminitis risk categories for WRT and TIFA was substantial at 0.79 (p <0.001), but moderate for WRT and ICLIA at 0.67 (p <0.001).Main limitations: Limited data from a single hospital and restricted readable range on the WRT.Conclusions: There was good statistical agreement between the WRT and TIFA testing methods and good concordance with the ICLIA.Results support the stable-side use of the WRT in UK equine practice.