Establishing Standards for Studying Renal Function in Mice through Measurements of Body Size-Adjusted Creatinine and Urea Levels
Methodological variation using duplicate samples. Urine was collected from C57BL/6 mice in metabolic cages for a period of 24 h. After centrifugation, the supernatant was removed for quantification of urea. The concentration of urea in the samples was quantified in duplicate, for each of two different methods, namely, the kinetic ultraviolet approach (kinetic reaction involving two time-points) and a colorimetric approach, using a fixed time period. (a) Assessment of the urea concentration in duplicate samples, measured by the enzymatic colorimetric method. (b) Assessment of the concentrations of urea in duplicate, measured by the ultraviolet method. (c) Evaluation of the differences between the duplicates by comparison of the two methodologies. The concentrations were expressed as mg per 24 h. Differences were considered significant when ().