Clearance tests as a diagnosis method of hepatobiliary system pathologies in animals

In present-day conditions of industrial agriculture, the animal's body works at the limit of its capabilities, which leads to degenerative diseases of various organs and systems. The development of ergonomic ways of modern diagnosis of these pathologies at the early stages contributes to the maintenance of quantitative and qualitative indices of productivity of animals and to the extension of the time of their economic use. The liver with a great number of functions performed is subjected to the highest load. The aim of the article is to review the available clearance tests in order to diagnose the pathology of the hepatobiliary system of animals at the early stage, considering advantages and disadvantages of the tests. As the result of the search of themed issues in various bibliographic databases there have been selected 45 mostly cited scientific articles. The article reviews such clearance tests as indocyanine green clearance test, aminopyrine breath test, sorbitol elimination test, galactose elimination test, phenylalanine breath test, and hepatobiliary scintigraphy method. Functional tests allow not only diagnosing and differentiating hepatopathologies, but also visualizing their course and liver recovery. Unlike laboratory tests, clearance tests make it possible to evaluate the work of the liver in dynamics. The disadvantages of clearance tests are lack of information for their wide use and frequency of particular differences in elimination of specific substances. To reduce the proportion of existing shortcomings, it is possible to combine clearance tests with other laboratory methods for diagnosing hepatopathy in animals.