Blood sugar (glucose) is our body’s fuel and we get this from the food we eat. To maintain a constant blood-glucose level the body produces insulin tasked with moving glucose from the blood into our body’s cells where it gets broken down to form energy.
A person with diabetes either lacks insulin and has to take insulin injections (type 1 diabetes) or is unable to use the insulin their body produces (type 2 diabetes). As a result excessive amounts of glucose circulate around the blood instead of getting converted into energy. Over time this can lead to serious organ damage making it is essential to keep blood sugar levels as stable as possible.
Although diabetes is characterised by blood sugar levels becoming too high, insulin treatment can sometimes cause levels to drop too low known medically as hypoglycaemia or hypo.
Self-monitoring of blood sugar is seen as an essential part of diabetes management and can inform you of any signs of complications. Diabetes UK says testing is important as going by ‘how you feel’ alone is not accurate enough.
Testing your blood glucose
Your diabetes care team will help you determine your personalised blood glucose targets. These will differ according to the type of diabetes that you have and by your age. As a general goal blood glucose levels should be kept as near to normal as possible, at a range of:
- 3.5–5.5mmol/l before meals
- less than 8mmol/l, 2 hours after meals
The best times to test are just before and two hours after the largest meal of the day.
Home blood glucose testing will give you an accurate picture of your blood glucose levels. To do this, prick the side of your finger with a finger-pricking device, put a drop of blood on a testing strip and read this with a meter. Your care team can advise you on which meter is best for you. It’s a good idea to keep a diary of your results to help your healthcare team monitor your needs.
If you use insulin you will need to test your blood glucose levels at least three times a day. Your care team will advise you as testing requirements differ depending on your treatment regime.
You should test more often if you are: pregnant, elderly, unwell or stressed, changing medication or planning to drive, exercise or operate machinery.
A major study carried out in the USA and Canada* showed that diabetics who tightly controlled their blood glucose levels had less risk of eye, kidney and nerve disease.
As well as daily testing, every two to six months your GP or diabetes care team will carry out a blood test called the HbA1c. This measures the amount of haemoglobin in your red blood cells. Haemoglobin is the oxygen-carrying substance that has glucose attached to it. The HbA1c test allows your diabetes team to see how stable your blood glucose has been over a period of months and whether your treatment plan is working.