title: Evaluation of a handheld point-of-care analyser for measurement of creatinine in cats.
abstract: Objectives The aim of the study was to evaluate whether a handheld creatinine analyser (StatSensor Xpress; SSXp), available for human patients, can be used to measure creatinine reliably in cats. Methods Analytical performance was evaluated by determining within- and between-run coefficient of variation (CV, %), total error observed (TEobs, %) and sigma metrics. Fifty client-owned cats presenting for investigation of clinical disease had creatinine measured simultaneously, using SSXp (whole blood and plasma) and a reference instrument (Konelab, serum); 48 paired samples were included in the study. Creatinine correlation between methodologies (SSXp vs Konelab) and sample types (SSXpwhole bloodvs SSXpplasma) was assessed by Spearman's correlation coefficient and agreement was determined using Bland-Altman difference plots. Each creatinine value was assigned an IRIS stage (1-4); correlation and agreement between Konelab and SSXp IRIS stages were evaluated. Results Within-run CV (4.23-8.85%), between-run CV (8.95-11.72%), TEobs(22.15-34.92%) and sigma metrics (⩽3) did not meet desired analytical requirements. Correlation between sample types was high (SSXpwhole bloodvs SSXpplasma; r = 0.89), and between instruments was high (SSXpwhole bloodvs Konelabserum; r = 0.85) to very high (SSXpplasmavs Konelabserum; r = 0.91). Konelab and SSXpwhole bloodIRIS scores exhibited high correlation ( r = 0.76). Packed cell volume did not significantly affect SSXp determination of creatinine. Bland-Altman difference plots identified a positive bias for the SSXp (7.13 μmol/l SSXpwhole blood; 20.23 μmol/l SSXpplasma) compared with the Konelab. Outliers (1/48 whole blood; 2/48 plasma) occurred exclusively at very high creatinine concentrations. The SSXp failed to identify 2/21 azotaemic cats. Conclusions and relevance Analytical performance of the SSXp in feline patients is not considered acceptable. The SSXp exhibited a high to very high correlation compared with the reference methodology but the two instruments cannot be used interchangeably. Improvements in the SSXp analytical performance are needed before its use can be recommended in feline clinical practice.
authors.affiliation: 1 School of Veterinary Sciences, University of Bristol, Langford, UK.|2 Small Animal Hospital, Langford Veterinary Services, Langford, UK.
authors.forename: Jenny
authors.initials: J
authors.lastname: Reeve
authors.affiliation: 1 School of Veterinary Sciences, University of Bristol, Langford, UK.|2 Small Animal Hospital, Langford Veterinary Services, Langford, UK.
authors.forename: Sheena
authors.initials: S
authors.lastname: Warman
authors.affiliation: 3 Vets Now Hospital, Glasgow, UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Lewis
authors.affiliation: 1 School of Veterinary Sciences, University of Bristol, Langford, UK.|2 Small Animal Hospital, Langford Veterinary Services, Langford, UK.
authors.forename: Natalie
authors.initials: N
authors.lastname: Watson
authors.affiliation: 1 School of Veterinary Sciences, University of Bristol, Langford, UK.|4 Diagnostic Laboratories, Langford Veterinary Services, Langford, UK.
authors.forename: Kostas
authors.initials: K
authors.lastname: Papasouliotis
mesh_terms: D000818:Animals; D001774:Blood Chemical Analysis / Q000295:instrumentation / Q000662:veterinary*; D002371:Cat Diseases / Q000097:blood; D002415:Cats / Q000097:blood*; D019411:Clinical Laboratory Techniques / Q000662:veterinary*; D003404:Creatinine / Q000097:blood; D055664:Electrochemical Techniques / Q000295:instrumentation; D006400:Hematocrit / Q000662:veterinary*; D006801:Humans; D019095:Point-of-Care Systems / Q000458:organization & administration*; D012015:Reference Standards; D012016:Reference Values
chemical_list: D003404:Creatinine