Objective: Morbidity and mortality of patients after orthotopic liver transplantation is influenced by the level of renal function significantly. With regard to the deviation of creatinine metabolism in patients with liver function impairment, we tried to study how far the analytical methods used for creatinine estimation could affect plasma levels creatinine in these patients. Material and Methods: The examinations were made in 50 adults before, during and after orthotopic liver transplantation. For the estimation of plasma creatinine there was used a modified Jaffé reaction and the enzymatic method, respectively. The statistic validation of results was made by means of statistical software MedCalc. Results: Median and CI 95 for (Pcr)J estimated by Jaffé reaction were 93.4 (88.4–99.3) µmol/l and those for estimated by enzymatic method (Pcr)E were 92.6 (86.7–100.6) µmol/l. There was a significant correlation between (Pcr) J and (Pcr) E: r = 0.991, P <0. 0001. The difference (Pcr)E – (Pcr)J decreased in relation to plasma level of bilirubin, r = -0.305, P <0. 0001. The difference (Pcr)E – (Pcr)J was -0. 1 µmol/l on average and 1.96 SD amounted 15.1 µmol/l. Conclusion: The systematic obtained results suggest that in patients before, during and in first 5 days after orthotopic liver transplantation, plasma creatinine levels estimated on the basis of Jaffé reaction and by enzymatic method from the clinical point of view are interchangeable.

        Key words: creatinine, enzymatic creatinine assay, modified Jaffé creatinine assay, liver transplantation.