If your not testing around meal times, then a fasting test is probably the best.
However, if you have issues with dawn phenomenon, then waiting at least half an hour after getting up, or later if you don't eat. Just about fifteen minutes prior to you preparing breakfast. If you keep to that every morning, then you will get an actual true figure close to an hba1c without taking blood.
As always keeping a record is always helpful to you and your doctor.