Liver diseases such as non-alcoholic fatty liver disease (NAFLD), alcoholic liver disease (ALD) and viral hepatitis have the potential to progress to cirrhosis and finally hepatocellular carcinoma (HCC). Early diagnosis and treatment of liver diseases is important since progression is likely and is associated with significant morbidity and mortality. However, in daily clinical practice no specific and non-invasive biomarkers are used for the diagnosis and follow-up of patients with liver diseases. It is known that patients with liver diseases produce compounds that can be excreted in breath as a consequence of metabolic processes, inflammation and/or oxidative stress. These are called volatile organic compounds (VOCs). Analysis of VOCs in exhaled air has been reported to provide valuable information in patients with chronic obstructive lung disease (COPD) and inflammatory bowel disease (IBD). Also, in patients with liver disease, exhaled VOCs have been detected.

The investigators hypothesize that analysis of VOCs in exhaled air of patients with liver diseases can be used for diagnosis and follow-up.

Inclusion Criteria:

• Established diagnosis of liver diseases based on laboratory, radiological and histological characteristics
• Age between 18 and 85 years

Exclusion Criteria:

• Inflammatory bowel disease
• Chronic obstructive lung disease, lung cancer, asthma
• Rheumatoid arthritis

The study population will include patients with various liver diseases visiting the outpatient clinic.