High blood sugar (hyperglycaemia)

If you have diabetes, you can find out if your blood sugar level is high by having a blood sugar (blood glucose) test. You may have regular tests by your care team or GP surgery, or you may have tests you can do at home. Types of diabetes test and high blood sugar levels Test done by a health professional to check your blood sugar level over the last 2 or 3 months (HbA1c test) 48 mmol/mol or over (6.5% if you're given a percentage) Test done by a health professional after not eating for a few hours (fasting glucose test) Over 7 mmol/L Home test done when you wake up or before eating at other times of the day Over 7 mmol/L Home test done at least 90 minutes after eating Over 11 mmol/L Important These blood sugar levels are a guide. Your levels may be different depending on your age and the type of diabetes you have. Check with your doctor or care team.

Symptoms of high blood sugar usually come on gradually and may only start when your blood sugar level gets very high. Common symptoms include: feeling very thirsty peeing a lot feeling weak or tired blurred vision losing weight

Common causes of high blood sugar in people with diabetes include: being unwell feeling stressed eating too much sugary or starchy food being less active than usual missing doses of diabetes medicine You can also get high blood sugar if your diabetes medicine is not working well, you're taking certain medicines (such as steroids) or you recently had an operation.

If you have diabetes, it's important to try to stop your blood sugar level getting too high. Do take any diabetes medicine you've been prescribed, as advised by your doctor or care team avoid eating too much sugary or starchy food try to find ways to manage stress exercise regularly lose weight if you're overweight follow advice from your doctor or care team about what to do while you're ill (sometimes called "sick day rules") Don’t do not skip or change doses of your diabetes medicine unless advised by your doctor or care team

It's not usually a serious problem if your blood sugar is sometimes slightly high for a short time. But high blood sugar can cause serious problems if it stays high for a long time or gets to a very high level. It can lead to: permanent damage to the nerves in your hands and feet ( peripheral neuropathy ) permanent damage to your eyes and problems with your sight ( diabetic retinopathy ) heart disease and stroke life-threatening conditions such as diabetic ketoacidosis If you have high blood sugar, your doctor or care team may ask you to test your blood or pee to check for ketones. A high level of ketones is a sign of diabetic ketoacidosis.