Gamma-glutamyl transpeptidase 100 U/L is on the high side. Normal reference values for gamma-glutamyl transpeptidase range from 11 to 50 U/L in men and from 7 to 32 U/L in women, so a level of 100 U/L is high. Gamma-glutamyl transpeptidase mainly comes from the liver and biliary system, and its elevated level suggests the possibility of biliary obstruction diseases such as primary biliary cirrhosis, sclerosing cholangitis, liver cancer, etc.; acute and chronic viral hepatitis, acute and chronic alcoholic hepatitis; fatty liver, pancreatitis, pancreatic tumor, prostate cancer, etc. may also show elevated levels of the enzyme. To sum up, it is recommended to consult a doctor as soon as possible, complete the relevant imaging and other examinations, make a clear diagnosis and standardize the diagnosis and treatment.