If this happened, and you also ate the candy bar, the result could easily have been a high reading at that time. A
glucose tolerance test could show whether your body reacts too strongly to glucose, and a hemoglobin a1c test could show whether your average glucose levels are running normal or not over the past few months. This is really the best test to see if your glucose levels are healthy or not, for they do change from hour to hour and any one test can have a misleading reading.