Comparison of three point-of-care blood testing instruments for rapid on-site health monitoring of Atlantic salmon Salmo salar

Biomarkers in blood are useful for assessing health and welfare in animals. This study evaluated the agreement among 3 point-of-care testing (POCT) instruments (Seamaty SMT-120VP, Mnchip Pointcare V2/V3, and Zoetis Vetscan VS2 analyzer) on Atlantic salmon Salmo salar. A repeatability study investigated internal measurement variation. In total, 60 plasma samples from adult fish were analyzed simultaneously using different rotors with multiple biomarkers. A comparison between blood and plasma was conducted on 35 blood samples. Lin's concordance correlation coefficient was <0.9 for all analyte comparisons between the 3 POCT except for bile acids; therefore, the McBride strength of agreement was generally poor and was moderate for bile acids. Internal measurement showed a low coefficient of variation for most analytes, except for aspartate aminotransferase (Pointcare V2/V3), alanine transaminase (Pointcare V2/V3), blood urea nitrogen (Pointcare V2/V3), and creatinine (Pointcare V2/V3, SMT-120VP). There was high concordance between whole blood and plasma samples for most analytes on both SMT-120VP and Pointcare V2/V3 systems, except for sodium, total bilirubin, and total CO2. This study underscores the necessity for system-specific calibration and validation of POCT systems like the Seamaty SMT-120VP and Mnchip Pointcare V2/V3 when used in aquaculture for clinical assessment of Atlantic salmon. The reproducibility study demonstrated that the precision of analysis was acceptable for most analytes. The comparison between whole blood and plasma suggests that whole blood can be used on-site to reduce the complexity of analysis. In summary, these systems offer promising tools for rapid on-site health monitoring in salmonid aquaculture but they require validation against gold-standard methods.