Tony is a 40 year old male who was persuaded by his wife to attend his NHS health check. He reports he is asymptomatic, feeling well and not on any regular medications. His BMI is 26 and he has never smoked or drank alcohol. All results have returned unremarkable except a significantly raised ALT of 221. You explain further investigations are necessary to establish a cause for this and to see if there is any underlying liver disease.
Which one of the following blood tests is not appropriate to include in his subsequent liver screen?