The purpose of this is to analyse human exhaled breath by means of a device called electronic nose(eNose) in patients with non-alcoholic fatty liver disease (NAFLD) as a way to non-invasive assessment of liver disease.This device is medically adapted and clinically validated in patients with lung conditions.

Human exhaled breath contains over 3000 volatile organic compounds (VOCs) that vary in relative concentration in health and disease. Metabolic disorders affecting the liver, such as NAFLD, produce disproportionate organic compounds produced as a by-product of metabolism and thus expired in exhaled breath, excreted in urine and detectable in blood. NAFLD prevalence is increasing and has reached epidemic proportions affecting 90% of obese adults and 22%-53% of obese children.Liver biopsy is the gold standard in diagnosing NAFLD, but it is unpleasant and can lead to complications. There is an unmet need to develop a non-invasive method of assessing liver disease. Comon Invent (Delft, Netherlands) together with the respiratory department at the Amsterdam Medical Centre (AMC), University of Amsterdam, have adapted the electronic nose known as SpiroNose as a prototype device for clinical use. Sensitive electronic sensors detect molecules in breath and generate signals. Complex algorithms and analytical technics allow pattern recognition of breath samples from different subjects. Well charaterised patients will be selected into clinical categories of non-alcoholic fatty liver disease with and without cirrhosis and be compared with healthy individuals.

Edinburgh will be the only site conducting this study. In addition to exhaled breath analysis, blood and urine will be collected to study the end products of metabolism.Furthermore, stool and urine collected from some subjects will be analysed to understand the role of gut bacteria in fermentation, metabolic products as a result cause VOC production.

Inclusion Criteria:

• Healthy individuals with no known or self declared medical illness with BMI (body mass index) within normal range (18.5-25)
• Non alcoholic fatty liver disease without cirrhosis
• Compensated (no evidence of ascites, encephalopathy) NAFLD cirrhosis; assessed by scoring system - Child's Pugh

Exclusion Criteria:

• Ongoing or recent (within last 6months) alcohol consumption more than 21 units per week for males and 14 units per week for females.
• BMI > 40
• Chronic respiratory disease e.g. Chronic obstructive pulmonary disease (COPD), asthma, interstitial fibrosis
• Use of antibiotics within last 4 weeks of sample collection and inflammatory bowel disease, irritable bowel syndrome, celiac sprue, or other chronic inflammatory diseases of the intestines (for intestinal microbiome analysis)
• Other known liver disease e.g. Primary Biliary Cholangitis/cirrhosis (PBC), Alcoholic liver disease (ALD), Autoimmune and hepatitis
• Inability to provide informed consent.
• Participation in other clinical intervention/drug trial

All eligible patients will have to consent to the study. The study population will consist of participants aged between 18 and 75 years old in the following cohorts (Healthy individuals, Non-alcoholic steatohepatitis (non-cirrhotic) and compensated Non-alcoholic liver cirrhosis). Each cohort will have 30 patients. There will be an equal number of participants for the healthy control group. In summary, the investigators aim to recruit 30 subject in the patient cohorts and 30 in healthy, totaling a number of 90 in the study

Individual participant data will not shared. Participants will be identified as a part of pre-defined cohort as categorised clinically.