¹³C Methacetin Breath Test for Assessment of Microsomal Liver Function: Methodology and Clinical Application

Abstract

Assessment of the liver function, and the need of constant monitoring of the organ's capacity, concerns not only patients with primary liver diseases, but also those at risk of hepatopathies secondary to other chronic diseases. Most commonly, the diagnostics is based on measurements of static biochemical parameters, which allow us to draw conclusions only indirectly about the function and the degree of damage of the organ. On the other hand, liver biopsy is an invasive procedure and therefore it is associated with a considerable risk of complications. Dynamic tests enable us to assess quantitatively the organ's functional reserve by analyzing the kinetics of the metabolization of the substrate by the liver. In practice applied are breath tests using substances such as aminopyrine, caffeine, methacetin, erythromycin (for assessment of the microsomal function); phenylalanine, galactose (for assessment of the cytosolic function); methionine, octanoate, ketoisocaproic acid (for assessment of the mitochondrial function). The test with 13C methacetin belongs to the best described and most widely applied methods in noninvasive liver function assessment. Due to the rising availability of this method, knowledge concerning its limitations and controversies regarding the methodology, as well as its usefulness in chosen groups of patients, seems to be vital.

Proto-Hormones Levels of Adipose Tissue, Interleukin-6 and Indicators of Detoxifying Function of the Liver in Patients With Hypertension and Obesity Combined With Non-Alcoholic Fatty Liver Disease

“…This test provides an opportunity to non-invasively evaluate the percentage of functioning hepatocytes, classify liver failure into cirrhotic and non-cirrhotic type and establish its degree according to the Child-Pugh criteria. The sensitivity and specificity of 13 C-metacetin breath test is >90 % [12,13]. The infrared spectroscope IRIS (Wagner, Germany) analyzed the air samples.…”

(13C)-Methacetin breath test provides evidence of subclinical liver dysfunction linked to fat storage but not lifestyle

“… 18 Examples of ( 13 C)-substrates include aminopyrine, phenacetin, caffeine, lidocaine, methacetin and erythromycin (targeting hepatocyte microsomal function), phenylalanine and galactose (targeting cytosolic enzymatic activity), methionine, ketoisocaproic acid (KICA), and octanoic acid (targeting mitochondrial function). ( 13 C)-Methacetin is rapidly metabolised, has a low cost, lacks toxicity, 19 and is available as ( 13 C)-methacetin breath test (MBT) for investigation of liver microsomal function in chronic liver diseases, 20 including chronic HCV infection 21 and liver cirrhosis. 22 ( 13 C)-MBT could separate patients with normal/NAFL from patients with NASH, 23 , 24 and was predictive for F3 or F4 fibrosis score in patients with histologically proven NASH.…”

13c-Methacetin Breathe Test in Early Diagnostics of Non-Alcoholic Fatty Liver Disease

“…The second parameter for analysis of the metabolism kinetics of 13 C labeled methacetin is the time from the substrate intake to a peak of 13 CO 2 elimination in exhaled air. A shift in the peak of the metabolism rate from 10 to 50 minutes indicates the development of fatty liver infiltration [10,11,12].…”