The test is started with placing a breathing mask on the patient's face, separating the inhaled from the exhaled air by two valves.
Consequently, the ratio of the  ¹³CO₂/¹²CO₂ is determined in the exhaled air over a period of 10 to 20 minutes to measure the individual baseline of each patient (Fig.
2).

 
After intravenous injection of ¹³C-methacetin the ratio of ¹³CO₂/¹²CO₂ increases subsequently and is quantified by a special device continuously and realtime at the bedside (FLIP).
Since the device is detecting the carbon dioxide ratio chronic lung diseases (e.g. COPD, fibrosis) do not influence test results.
The turnover of ¹³C-methacetin can be continuously determined using kinetic analysis.
The LiMAx (maximum liver function capacity) is defined as the maximum value of the substrate conversion normalized to body weight.
The test is started with placing a breathing mask on the patient's face, separating the inhaled from the exhaled air by two valves. Consequently, the ratio of the  ¹³CO₂/¹²CO₂ is determined in the exhaled air over a period of 10 to 20 minutes to measure the individual baseline of each patient (Fig. 2).
 
After intravenous injection of ¹³C-methacetin the ratio of ¹³CO₂/¹²CO₂ increases subsequently and is quantified by a special device continuously and realtime at the bedside (FLIP). Since the device is detecting the carbon dioxide ratio chronic lung diseases (e.g. COPD, fibrosis) do not influence test results. The turnover of ¹³C-methacetin can be continuously determined using kinetic analysis. The LiMAx (maximum liver function capacity) is defined as the maximum value of the substrate conversion normalized to body weight.
LiMAx test