Assessment of the Nova StatSensor whole blood point-of-care creatinine analyzer for the measurement of kidney function in screening for chronic kidney disease

Background: Point-of-care testing for creatinine using a fingerprick sample and resultant estimated glomerular filtration rate has potential for screening for chronic kidney disease in community settings. This study assessed the applicability of the Nova StatSensor creatinine analyzer for this purpose. Methods: Fingerprick samples from 100 patients (63 renal, 37 healthy volunteers; range 46-962 μmol/L) were assayed using two StatSensor analyzers. Lithium heparin venous plasma samples collected simultaneously were assayed in duplicate using the isotope dilution mass spectrometry-aligned Roche Creatinine Plus enzymatic assay on a Hitachi Modular P unit. Method comparison statistics and the ability of the StatSensor to correctly categorise estimated glomerular filtration rate above or below 60 mL/min were calculated pre- and post-alignment with the laboratory method. Results: StatSensor 1 creatinine results (y) were much lower than the laboratory (y=0.75x+10.2, average bias -47.3, 95% limits of agreement -208 to +113 μmol/L). For estimated glomerular filtration rates above or below 60 mL/min, 100% and 87% of results respectively agreed with the laboratory estimated glomerular filtration rate (79% and 96% post-alignment). StatSensor 2 statistics were similar. The 95% limits of agreement between StatSensor creatinine results were -35 to +34 μmol/L. Conclusions: Isotope dilution mass spectrometry alignment of the StatSensor will identify most patients with estimated glomerular filtration rate <60 mL/min, but there will be many falsely low estimated glomerular filtration rate results that require laboratory validation. Creatinine results need improvement.