LiMAx test

LiMAx test is a non-invasive medical procedure used to measure the maximum liver function capacity (LiMAx). The test is based on the metabolism of a 13C-labelled substance, methacetin, which is exclusively metabolized by the liver enzyme cytochrome P450 1A2 (CYP1A2). The LiMAx test is used to assess liver function in various clinical situations, such as before and after liver surgery, in liver transplantation, and in patients with liver diseases.

Procedure

The LiMAx test involves the intravenous administration of 13C-methacetin. The 13C-methacetin is metabolized by the liver to 13CO2 and paracetamol. The 13CO2 is exhaled and can be measured in the breath. The rate of 13CO2 production is directly proportional to the activity of the liver enzyme CYP1A2, and thus reflects the liver function.

Clinical applications

The LiMAx test is used in various clinical situations to assess liver function. These include:

• Preoperative assessment of liver function before liver surgery
• Postoperative monitoring of liver function after liver surgery
• Assessment of liver function in liver transplantation
• Assessment of liver function in patients with liver diseases, such as cirrhosis and hepatitis

Advantages

The LiMAx test has several advantages over other methods of assessing liver function. These include:

• Non-invasiveness: The test does not require any invasive procedures, such as liver biopsy.
• Specificity: The test specifically measures the activity of the liver enzyme CYP1A2, which is exclusively involved in the metabolism of 13C-methacetin.
• Sensitivity: The test is sensitive to changes in liver function, and can detect even minor impairments in liver function.

Limitations

The LiMAx test has some limitations. These include:

• The test requires specialized equipment to measure 13CO2 in the breath.
• The test may not be suitable for patients with severe lung disease, as this may affect the exhalation of 13CO2.

See also

• Liver function tests
• Liver surgery
• Liver transplantation
• Liver diseases
• Cytochrome P450 1A2

LiMAx test Resources
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