The H2 monitor LactoFAN2 The LactoFAN2 is a powerful diagnostic tool for measuring expired Hydrogen concentrations. From a single breath manoeuvre, measurements are instantly displayed on the large, easy to read liquid crystal display. Main applications of the LactoFAN are the Lactose intolerance test and the easy indication of intestinal lactose malabsorption by monitoring the exhaled H2 after ingestion of lactose.