A 25 year old woman presents to the GP following a private health check. She reports no symptoms and her examination is normal. Her blood test demonstrates that her ALT is 31 U/L (normal less than 35 U/L), AST is 29 U/L (normal less than 35 U/L), Alkaline Phosphatase is 111 U/L (normal range, 30-130 U/L) and bilirubin is 30 umol/L (normal less than 21 umol/L).
What is the most likely diagnosis?