I had raised GGTs after my Doctor tested me once. I get checked becaus of the medication I take for high BP. However the test was unannounced and just after Valentines night dinner with my pregnant wife. Naturally I was forced to imbibe the entire contents of a bottle of wine all by myself
No wonder it was high.
He sent me a letter which just stopped short of suggesting the phone number of the nearest AA group. I went back later, properly fasted and without any wine in my system and passed easily.
So learned not to have any drink for a couple of days before a visit. Which isn't hard in my case because having a giggling one year old boy who sits on your head at 6 in the morning and pulls your hair, hangovers are to be avoided.