Analytical Evaluation of ABL90 Flex Plus Blood Gas Analyzer for Urea and Creatinine

Background Acute kidney injury is a common complication among hospitalized patients. The availability of creatinine and urea measurements as point-of-care testing provides an alternative strategy to monitor renal function and develop prevention strategies, especially in the emergency services, where reducing waiting times and rapid clinical decisions may be required. Objective The aim of this study was to evaluate if creatinine and urea measurements are interchangeable between ABL90 Flex Plus and three common central laboratory methods. Methods With a multicenter design, creatinine and urea were first analyzed by ABL90 Flex Plus and then by laboratory method: Dimension Vista 1500, Cobas c702, and Architect c16000 according to Clinical and Laboratory Standards Institute EP09-A3 protocol. All measurements were performed in duplicate. Results were evaluated using Passing-Bablok regression and Bland-Altman comparison. Interchangeability of patient results was verified at different clinical decision levels. Results Passing-Bablok regression between the 3 central laboratory methods and ABL90 Flex Plus showed correlation coefficients over 0.998 for creatinine and 0.994 for urea, and despite the presence of proportional and/or constant bias observed in the study, estimated difference was lower than the allowable difference (±15.6% for urea and ±8.9% for creatinine) at clinical decision levels in all cases. Conclusion Creatinine and urea measurements are interchangeable using ABL90 Flex Plus blood gas analyzer compared with 3 central laboratory methods, ensuring no impact on patient care using indistinctly any analyzer.