Establishing Standards for Studying Renal Function in Mice through Measurements of Body Size-Adjusted Creatinine and Urea Levels
Levey-Jennings charts and evaluation of Westgard rules. The control samples were obtained from the biotechnical company and the variations (mean and standard deviation) were established and compared with those of the manufacturer, obtained from 20 different trials. After the collection and preparation of all biological samples, we inserted the control samples among the test samples, randomly, and quantified the concentrations of urea and creatinine by spectrophotometry. In (a), we evaluated the concentrations of creatinine by the colorimetric method (red-yellow), using picrate in an alkaline solution and reading at 500 nm, using 40 control points with an average of 1.18 and a 0.30 to 1 s deviation. In (b), we evaluated the concentrations of urea by the modified method of Berthelot (reading at 580 nm), using eight control points, with an average of 35.5 and a deviation of 3.60 to 1 s. In (c), we evaluated the concentrations of urea spectrophotometrically at 340 nm, using 20 control points, with an average of 29.8 and a deviation of 5.40 to 1 s. For statistical evaluation, we used the deviation distribution of samples (1 s, 2 s, and 3 s) as well as the Westgard rules.