Whatever is causing the abnormal liver blood tests could cause fatigue.
Doctors call these liver enzymes in the blood, liver function tests or LFTs. The most important LFTs are ALT, AST, alkaline phosphatase (AP), and bilirubin.
There are many causes of elevated LFTs, such as chronic viral hepatitis B and C, inflammation related to alcohol (alcoholic hepatitis), and cancer. Medical tests would be necessary to diagnose the cause of the abnormal LFTs and fatigue, such as more blood tests, scan of the abdomen and liver, and liver biopsy.