The way in which diabetes is diagnosed is now changing but blood tests will need to be done to confirm diagnosis of Diabetes. You may no longer need to fast before a blood glucose test.
In order to diagnose Type 1 Diabetes your doctor will take a thorough history of how you have been feeling, test your blood and urine, and check your weight. The symptoms of type 1 diabetes are very acute. Usually your doctor will be able to diagnose by checking your urine for ketones and a random blood glucose test. (normal range is between
4-7mmol/l). Having made the diagnosis you will be sent to the Diabetes Unit at the hospital usually the same day.
For Type 2 Diabetes it is a little more complicated as many people do not feel unwell at diagnosis. If your doctor or nurse suspects that you may have diabetes they will in most perform a random blood test, which does not require fasting. Also known as HbA1c test
The World health organisation WHO consensus say we should be using HbA1c for diagnosing diabetes.
Download our HBA1c booklet
In some complex cases a Fasting Blood Glucose Test (FGT) may be required which involves fasting (not eating or drinking anything) from the night before the test, arriving at the surgery early in the morning before breakfast and the GP/nurse taking a blood sample. Your GP will decide this.
The other blood test that is sometimes done is a Oral Glucose Tolerance Test (GTT) This involves two blood tests within two hours, one fasted and one two hours later after drinking a sugary drink (containing 150 grams of carbohydrate eg Lucozade)