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