Objective: In the 2nd part of work, we tried to compare urine concentration of creatinine and the renal clearance of creatinine in 50 patients before, during and first 5 days after orthotopic liver transplantation that were estimated by modification of the Jaffé reaction and by enzymatic assay, respectively. Material and Methods: The examinations were made in 50 adults before, during and after orthotopic liver transplantation. For the urine creatinine there were used modified Jaffé reaction and enzymatic method. The calculation of renal clearence creatinine, the calculation of prediction clearence creatinine by means Cockcroft and Gault and the calculation of prediction glomerular filtration by means MDRD were performed. The statistic validations of results were made by means of statistical software MedCalc. Results: For (Ucr)J median and CI95 were three, 3.60 (3.20–4. 00) mmol/l and those for (Ucr)E 3.30 (2.90–3.70) mmol/l. There was a significant correlation between (Ucr)J and (Ucr)E (r = 0.991, P < 0. 0001). The systematic difference (Ucr) E – (Ucr)J was -0.40 mmol/l on average and 1.96 SD amounted 0.48 mmol/l. Median and CI 95 for (Ccr)J were 1.26 (1.14–1.38) ml/s/1.73 m2 and those for (Ccr)E 1.13 (1.04–1.26) ml/s/1.73m2. There was a significant correlation between (Ccr)J and (Ccr)E (r = 0.964, P < 0. 0001). The systematic difference (Ccr)E and (Ccr)J was -0.11 ml/s/1.73 m2 on average and 1. 96 SD amounted 0. 27 ml/s/1.73 m2. Conclusion: The obtained results suggest that values difference of concentration urine creatinine and clearence creatinine amounting such values that are significant from the clinical point of view. Therefore, the results of urine creatinine and clearance creatinine, estimated based on Jaffé reaction and by enzymatic method, are not interchangeable.

        Key words: creatinine assay, modified Jaffé creatinine assay, clearance of creatinine.