Self-monitoring and blood sugar control

Written by: 
Steve Chaplin, medical writer
Keeping tight control of blood sugar (glucose) levels is important for people with diabetes. Having high glucose levels over a long period damages blood vessels and significantly increases your risk of developing complications, including heart, kidney, nerve and eye disease. Monitoring your blood glucose levels at home may help you to adjust your treatment more easily, so that you can keep your blood glucose levels under control. If you want to measure your blood sugar levels, or those of your child, you need to choose the meter and testing materials that suit you best. There are many different designs of meter, but they all work on the same basic principle:
  • A drop of blood is produced by pricking the side of a finger with a finger-pricking device or a lancet
  • The drop is placed on a testing strip and inserted into the meter, which gives a readout after a period ranging from a few seconds to a minute.
Choosing a meter Your doctor or diabetes nurse can advise you about choosing a meter. It may also help to ask other people with diabetes about their experiences with different types of meter. The factors to consider include the below. Cost Which meters does your health insurance or health service pay for? Do they pay for the test strips too? Convenience Meters come in different sizes and run on batteries; some are small enough for children to carry. Ease of use
  • How easy is the meter to use? Getting the technique wrong could give you a misleading measurement. Ask yourself:
  • Is the meter fiddly to handle?
  • How easily can you remove the test strips from their wrapping?
  • How much blood does the meter need for a measurement?
  • Is the equipment easy to clean?
Remember, you could be using the meter several times a day - any problems that seem trivial at first could become irritating with time. Display Can you see the display well enough to use the meter easily? Some meters have large displays for people with impaired vision. Most devices can download their results onto a computer, which can then convert the text into speech if necessary. Support Can you access support and help with using the meter if you need it? Are your doctors and nurses familiar with the meter? Does the manufacturer have a telephone helpline or a website? Does the meter come with clear instructions or a video? Advanced meter functions Do you need the meter to store lots of readings? Do you need information in a language other than English? Do you need an alarm function? Replacement supplies How easy it is to acquire new test strips? Can you get them from the local pharmacy or hospital, or do you need to order them? Do they have a long enough shelf life? Do you need them to work in hot or humid conditions? You can talk to anyone in your healthcare team about how often to test your blood glucose and how to adjust your treatment according to the results. What's the difference between self-monitoring and HbA1C? Meters measure the concentration (level) of glucose (a type of sugar) in plasma (the clear, straw-coloured liquid that is part of blood). Glucose concentrations in plasma are 11-12 per cent higher than those in whole blood. Meter measurements are usually taken just before a meal, giving you the fasting plasma glucose level (often shortened to FPG). This tells you how much insulin you need to inject if you have insulin therapy. HbA1C is a blood test that offers a way of monitoring how well your diabetes treatment is controlling your blood glucose over a long period of time; it is usually measured at least once a year. HbA1C stands for glycosylated haemoglobin A1C. It is the concentration of haemoglobin (the oxygen-carrying protein in your blood) that has combined with glucose and it reflects the average level of plasma glucose during the previous three months. If your diabetes treatment has been keeping your plasma glucose low, the HbA1C will be low; if HbA1C is too high, your treatment may be changed. You usually agree a target for HbA1C with your doctor or nurse, or they may advise you what they think is best. How do diet and sports affect self-monitoring? Major changes to your diet (such as fasting) and to your energy needs (such as when you play sport) have significant effects on blood glucose levels. If you don't adjust your food intake and insulin dose, you may get hypoglycaemia or hyperglycaemia. Your health could be at risk if you attempt to fast, start to play sports or begin a physical training routine without help and support. It is vital for people with diabetes to discuss their plans with a doctor or nurse before making any major changes to their usual diet and exercise habits, and to take advice from experts such as dieticians and sports practitioners. Fasting Although it is possible to undertake a fast if you have diabetes, not everyone can do this without risking severe hypoglycaemia. In general, fasting reduces your energy intake. You will need less insulin (and may need to change the type of insulin you use) and you will need to monitor your blood glucose more frequently. If you do experience hypoglycaemia while fasting, you will need to break your fast. It helps to eat especially healthily before fasting (particularly complex carbohydrates like oats and unpolished rice) and when you break your fast. It is also important to remember that some traditional foods may be high in fats and sugar. People with diabetes are often excused the requirement for fasting for religious festivals - your religious leaders will be able to offer guidance. Sports Provided that you look after yourself, your diabetes need not stop you enjoying sports - with careful preparation, you can even run a marathon. The following steps and precautions are essential for any event involving sustained physical exertion. It is important that you:
  • Prepare carefully through training
  • Eat more carbohydrates and eat more frequently
  • Make sure you drink enough water
  • Measure your blood glucose more frequently
  • Be sure to have enough snacks and insulin available - exactly what you need to do depends on the intensity and duration of the exercise and the weather conditions (temperature, humidity and so on)
  • Tell the event organisers that you have diabetes - note that this may affect their insurance and your eligibility to participate
  • Have a support team and carry identification that tells others what to do if you do develop hypoglycaemia.
Your insulin requirement may change during training: regular exercise reduces the body's resistance to insulin and insulin absorption is increased from sites that are physically active during exercise (for example, the abdominal wall). There is also risk of injury to your feet from running. Diet and diabetes Resources on meters and monitoring
  • 'Blood glucose meters.' American Diabetes Association. Link
  • 'Blood glucose.' Diabetes UK. Link
  • 'Guide to Blood Glucose Meters.' Link
  • Resources on diet
  • 'Dietary advice during Ramadan.' Leicestershire Diabetes website, University Hospitals of Leicester NHS Trust. Link
  • Resourcecs on exercise
  • 'Strenuous sports.' Diabetes UK. Link
  • 'Diabetes and fitness - types of exercise.' Link
  • 'Diabetes and sport.' Link