LiMAx test

A liver function test based on breath analysis

Overview

The LiMAx test (Liver Maximum Capacity test) is a diagnostic procedure used to assess the functional capacity of the liver. It is based on the measurement of the liver's ability to metabolize a specific substrate, methacetin, which is administered intravenously. The test provides a quantitative evaluation of liver function by analyzing the exhaled breath of the patient.

Metabolism of Methacetin

Principle

The LiMAx test utilizes the metabolism of methacetin, a compound that is specifically processed by the liver enzyme cytochrome P450 1A2. When methacetin is metabolized, it is converted into acetaminophen and carbon dioxide (CO2). The CO2 is then exhaled and can be measured in the breath of the patient. The rate of CO2 production is directly proportional to the liver's metabolic capacity.

Procedure

The procedure for the LiMAx test involves the following steps:

1. Preparation: The patient is required to fast for a certain period before the test to ensure accurate results. 2. Administration: Methacetin is administered intravenously. 3. Breath Analysis: The patient breathes into a device that measures the concentration of CO2 in the exhaled air over a period of time. 4. Data Interpretation: The data collected is analyzed to determine the liver's metabolic capacity.

Clinical Applications

The LiMAx test is used in various clinical settings, including:

• Preoperative Assessment: To evaluate liver function before major liver surgery, such as hepatectomy or liver transplantation.
• Monitoring Liver Disease: To monitor the progression of chronic liver diseases like cirrhosis or hepatitis.
• Postoperative Monitoring: To assess liver function recovery after surgery.

Advantages

The LiMAx test offers several advantages over traditional liver function tests:

• Non-invasive: It requires only a breath sample, making it less invasive than liver biopsies.
• Rapid Results: Provides quick results, which are crucial in acute settings.
• Quantitative: Offers a direct measurement of liver function capacity.

LiMAx test process

Limitations

Despite its advantages, the LiMAx test has some limitations:

• Availability: The test requires specialized equipment and is not widely available in all medical centers.
• Cost: It may be more expensive than traditional liver function tests.

Related pages

• Liver function tests
• Cytochrome P450
• Hepatectomy
• Liver transplantation