How long of abstinence from alcohol will give a normal cdt test level. i need this to regain my driving licence?

24 hours: 24 hours should do the trick. If you want to be doubly safe, make it 48!

NinetyDaysToFreedom: The half-life of Carbohydrate-Deficient Transferrin (CDT, the substance tested in the CDT Test) is on average 17 days. And it takes about 5 half-lives to get near zero, assuming you stopped all alcohol intake. A half- life is the time for the amount to halve (duh).So 5X17=85 days so round up to 90 days or three months.Suggestion, at that point you'll be well on your way to having stopped drinking!