Review article: the assessment of liver function using breath tests

Abstract

Hepatologists have long sought to develop a test for assessing liver function, but this aim has been stalled by the complexity of the liver and its diverse functions. Results of metabolic tests, including breath tests, correlate with clinical and histological parameters of patients with liver disorders; however, these tests tend to be cumbersome and impractical for everyday use. The recent development of a real-time, point-of-care liver function breath test has made it straightforward to assess the metabolic function of the liver. To review the available data on the use of breath tests for assessing liver reserve in various conditions and their application in various clinical hepatology settings. The (13)C-methacetin breath test enables accurate follow-up of patients with acute or chronic liver damage, where overall hepatic function is significantly suppressed by known causes of liver disorders, including acute, sub-acute or chronic conditions. The metabolic breath test can detect both gradual and spontaneous improvements in liver function and the effects of treatment. Breath testing that provides continuous quantification of methacetin metabolism may be a sensitive tool for the diagnosis and follow-up of patients with liver disorders.