Diagnosis

Your doctor sets your target blood sugar range. For many people who have diabetes, Mayo Clinic generally recommends target blood sugar levels that are:

  • Between 80 and 120 mg/dL (4 and 7 mmol/L) for people age 59 and younger who have no other underlying medical conditions
  • Between 100 and 140 mg/dL (6 and 8 mmol/L) for people age 60 and older, those who have other medical conditions, such as heart, lung or kidney disease, or those who have a history of low blood sugar (hypoglycemia) or who have difficulty recognizing the symptoms of hypoglycemia

Your target blood sugar range may differ, especially if you're pregnant or you develop diabetes complications. Your target blood sugar range may change as you get older, too. Sometimes, reaching your target blood sugar range is a challenge.

Home blood sugar monitoring

Routine blood sugar monitoring with a blood glucose meter is the best way to be sure that your treatment plan is keeping your blood sugar within your goal range. Check your blood sugar as often as your doctor recommends.

If you have any signs or symptoms of severe hyperglycemia — even if they're subtle — check your blood sugar level. If your blood sugar level is 240 mg/dL (13 mmol/L) or above, use an over-the-counter urine ketones test kit. If the urine test is positive, your body may have started making the changes that can lead to diabetic ketoacidosis. You'll need your doctor's help to lower your blood sugar level safely.

Glycated hemoglobin (A1C) test

During an appointment, your doctor may conduct an A1C test. This blood test indicates your average blood sugar level for the past two to three months. It works by measuring the percentage of blood sugar attached to hemoglobin, the oxygen-carrying protein in red blood cells.

An A1C level of 7 percent or less means that your treatment plan is working and that your blood sugar was consistently within the target range. If your A1C level is higher than 7 percent, your blood sugar, on average, was above the normal range. In this case, your doctor may recommend a change in your diabetes treatment plan.

However, for some people, especially the elderly, people with other medical conditions, or advanced diabetes complications, a higher A1C level of up to 8 percent may be appropriate.

Keep in mind that the normal range for A1C results may vary somewhat among labs. If you consult a new doctor or use a different lab, it's important to consider this possible variation when interpreting your A1C test results.

How often you need the A1C test depends on the type of diabetes you have and how well you're managing your blood sugar. Most people with diabetes, however, receive this test between two and four times a year.

Treatment

Home treatment

Talk to your doctor about managing your blood sugar and understand how different treatments can help keep your glucose levels within your goal range. Your doctor may suggest the following treatments:

  • Get physical. Regular exercise is often an effective way to control your blood sugar. However, don't exercise if ketones are present in your urine. This can drive your blood sugar even higher.
  • Take your medication as directed. If you have frequent episodes of hyperglycemia, your doctor may adjust the dosage or timing of your medication.
  • Follow your diabetes eating plan. It helps to eat less and avoid sugary beverages. If you're having trouble sticking to your meal plan, ask your doctor or dietitian for help.
  • Check your blood sugar. Monitor your blood glucose as directed by your doctor. Check more frequently if you're ill or you're concerned about severe hyperglycemia or hypoglycemia.
  • Adjust your insulin doses to control hyperglycemia. Adjustments to your insulin program or a supplement of short-acting insulin can help control hyperglycemia. A supplement is an extra dose of insulin used to help temporarily correct a high blood sugar level. Ask your doctor how often you need an insulin supplement if you have high blood sugar.

Emergency treatment for severe hyperglycemia

If you have signs and symptoms of diabetic ketoacidosis and hyperosmolar hyperglycemic syndrome, you may be treated in the emergency room or admitted to the hospital. Emergency treatment can lower your blood sugar to a normal range. Treatment usually includes:

  • Fluid replacement. You'll receive fluids — either orally or through a vein (intravenously) — until you're rehydrated. The fluids replace those you've lost through excessive urination, as well as help dilute the excess sugar in your blood.
  • Electrolyte replacement. Electrolytes are minerals in your blood that are necessary for your tissues to function properly. The absence of insulin can lower the level of several electrolytes in your blood. You'll receive electrolytes through your veins to help keep your heart, muscles and nerve cells functioning normally.
  • Insulin therapy. Insulin reverses the processes that cause ketones to build up in your blood. Along with fluids and electrolytes, you'll receive insulin therapy — usually through a vein.

As your body chemistry returns to normal, your doctor will consider what may have triggered the severe hyperglycemia. Depending on the circumstances, you may need additional treatment.

If your doctor suspects a bacterial infection, he or she may prescribe antibiotics. If a heart attack seems possible, your doctor may recommend further evaluation of your heart.

Preparing for your appointment

If you have trouble keeping your blood sugar within the desired range, schedule an appointment to see your doctor. He or she can help you make changes to better manage your diabetes.

Here's some information to help you get ready for your appointment and to know what to expect from your doctor.

What you can do

  • Be aware of any preappointment restrictions. If your doctor is going to test your blood sugar, he or she may ask you to refrain from eating or drinking anything but water for up to eight hours before your appointment. When you're making an appointment, ask if you should fast.
  • Write down key personal information, including any major stresses or recent life changes.
  • Make a list of all medications, vitamins and supplements you take.
  • Create a record of metered glucose values. Give your doctor a written or printed record of your blood glucose values, times and medication. Using the record, your doctor can recognize trends and offer advice on how to prevent hyperglycemia.
  • Write down questions to ask your doctor. Be clear about aspects of your diabetes management that you need more information on.
  • Be aware if you need any prescription refills. Your doctor can renew your prescriptions while you're there.

For hyperglycemia, questions you may want to ask include:

  • How often do I need to monitor my blood sugar?
  • What is my goal range?
  • How do diet and exercise affect my blood sugar?
  • When do I test for ketones?
  • How can I prevent high blood sugar?
  • Do I need to worry about low blood sugar? What are the signs and symptoms I need to watch out for?
  • What kind of follow-up, if any, will I need?

Sick-day planning

Illness or infections can cause your blood sugar to rise, so it's important to plan for these situations. Talk to your doctor about creating a sick-day plan. Questions to ask include:

  • How often should I monitor my blood sugar during an illness?
  • Does my insulin injection or oral diabetes pill dose change when I'm sick?
  • When should I test for ketones?
  • What if I'm unable to eat or drink?
  • When should I seek medical help?
April 18, 2015
References
  1. Hyperglycemia (high blood glucose). American Diabetes Association. http://www.diabetes.org/living-with-diabetes/treatment-and-care/blood-glucose-control/hyperglycemia.html. Accessed March 24, 2015.
  2. Your guide to diabetes: Type 1 and type 2. National Institute of Diabetes and Digestive and Kidney Diseases. http://diabetes.niddk.nih.gov/dm/pubs/type1and2/index.aspx. Accessed March 24, 2015.
  3. McCulloch DK. Management of persistent hyperglycemia in type 2 diabetes mellitus. http://www.uptodate.com/home. Accessed March 24, 2015.
  4. Kitabchi AE, et al. Diabetic ketoacidosis and hyperosmolar hyperglycemic state in adults: Treatment. http://www.uptodate.com/home. Accessed March 24, 2015.
  5. Castro MR (expert opinion). Mayo Clinic, Rochester, Minn. March 24, 2015.
  6. Steele AM, et al. Prevalence of vascular complications among patients with glucokinase mutations among prolonged, mild hyperglycemia. Journal of the American Medical Association. 2014;311(3):279.
  7. Standards of medical care in diabetes — A position statement of the American Diabetes Association. Diabetes Care. 2015;38(suppl):S33.

Hyperglycemia in diabetes