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.