CF-related liver disease (CFLD) occurs in up to 30% of people with CF. However, it is only a serious clinical problem in a minority of individuals. Often there is an abnormality of liver function tests and in some of these, some changes in the liver. In a small percentage of patients, cirrhosis (scarring of the liver) develops. If the scarring becomes severe, liver transplant may be necessary. Liver function is monitored through blood tests and abdominal ultrasound.