Problems of quantitative estimation of excretory kidney function based on creatinin

Abstract

This review presents the possibility of using serum creatinine as an endogenous indicator of the functional state of the kidneys. The results of scientific research are analyzed, which shows the information content of the use of this indicator for assessing glomerular filtration rate (GFR). The features of laboratory methods for determining serum creatinine are considered. Particular attention is paid to information about the errors and variability of measurements of standardized methods obtained in laboratories of different countries. In addition to the physiological reasons that make serum creatinine an imperfect marker for GFR, there are analytical measurement errors, which, in turn, can also distort true results. Since the relationship between serum creatinine and GFR is hyperbolic, analytical errors will affect not only the accuracy of the calculation equations based on it. The introduction of standardization of routine methods for measuring serum creatinine from a reference sample improved the assessment of GFR by reducing the bias of the results of measuring creatinine from its true value. To increase the accuracy and reliability of standardized methods, it is necessary to continue research in this direction. In real clinical practice, all the limitations and assumptions of a specific method of measuring creatinine should be taken into account in order to avoid incorrect interpretation of the results when assessing the functional ability and staging of chronic kidney disease. For prospective observation of a specific patient, the same GFR calculation formula and the same method for measuring serum creatinine should be used.