Methods for assessing the functional reserve of the kidneys

The problem of studying the functional reserve of the kidneys attracted the attention of nephrologists about 40 years ago. However, to date, a single protocol for performing functional load tests has not been developed. When assessing the excretory function of the kidneys, nephrologists, as before, are guided by the value of the glomerular filtration rate. However, in two patients of the same age and gender, the same value of this indicator cannot be interpreted unambiguously. In this article, we consider the technical features of performing load tests using egg white, "red meat", a mixture of amino acids, 0.5 % sodium chloride solution. All of them require time and labor resources. This limits the possibilities of their use in outpatient settings. We believe that it is necessary to determine the functional reserve in patients without primary kidney pathology, that is, persons with an established diagnosis of diabetes mellitus or hypertension with a disease duration of at least 5 years. Serious nephroprotective measures in them are recommended to begin only at the stage of chronic kidney disease C3a. It is possible that such a late start of secondary prevention partly explains the increase in the proportion of such patients in hemodialysis centers.