How long do you wait after drinking alcohol before having a full blood test?

Depends on the. Test concerned. Blood alcohol will dissipate in about 24 hours or less. Other changes in blood components, e.g. Carbohydrate deficient transferrin may be abnormal for up to two weeks, particularly after drinking for a few days. Ggt and other liver enzymes may be elevated, even after one drinking episode, for 2-3 days.