The primary objective is to determine the galactose single point (GSP) cutoff values to discriminate subjects with different hepatic function. The secondary objective is to analyze the correlations between GSP and other hepatic function assessment methods among this trial subjects.

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease, including the potential for progression to nonalcoholic steatohepatitis (NASH), followed by fibrosis and ultimately cirrhosis. The gold standard to evaluate fibrosis in patients with NAFLD is liver biopsy. The investigators aimed to evaluate the clinical utility of using the galactose single point (GSP) test which recommended by the US FDA to quantitatively measure liver function in patients with NAFLD.

Inclusion Criteria:

Subject must fulfill all of the following criteria to be eligible for the study:

1. Male or female with age between 20-80.
2. Ability and willingness to provide informed consent, adhere to the study visit schedule and complete all study assessments and language specific questionnaires.

Exclusion Criteria:

Any of the following criteria will disqualify the subject from participation:

1. History of serious allergic reaction to galactose and have galactosemia.
2. History of receiving total gastrectomy, subtotal gastrectomy, celiac disease, or small intestinal resection.
3. History of diabetes mellitus.
4. Subjects are children or handicapped people.
5. Subjects with any other reasons considered by the investigator not in the condition to enter into the trial.