What is my target blood sugar range? How often should I check my blood sugar? What do these numbers mean? Are there patterns that show I need to change my diabetes treatment? What changes need to be made to my diabetes care plan?

Top of Page. Getting Tested What is Low Blood Sugar hypoglycemia? What is High Blood Sugar hyperglycemia? Education and Support. Last Reviewed: December 30, Source: Centers for Disease Control and Prevention.

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Will I need follow-up care? Sick-day planning Illness or infections can cause your blood sugar to rise, so it's important to plan for these situations. Questions to ask include: How often should I monitor my blood sugar when I'm sick? Does my insulin injection or oral diabetes pill dose change when I'm sick?

When should I test for ketones? What if I can't eat or drink? When should I seek medical help? By Mayo Clinic Staff. Aug 20, Show References.

Hyperglycemia high blood glucose. American Diabetes Association. Accessed July 6, What is diabetes? National Institute of Diabetes and Digestive and Kidney Diseases. Wexler DJ. Management of persistent hyperglycemia in type 2 diabetes mellitus.

Hirsch IB, et al. Diabetic ketoacidosis and hyperosmolar hyperglycemic state in adults: Clinical features, evaluation, and diagnosis. Managing diabetes.

Inzucchi SE, et al. Glycemic control and vascular complications in type 2 diabetes mellitus. Comprehensive medical evaluation and assessment of comorbidities: Standards of Medical Care in Diabetes — Diabetes Care.

The big picture: Checking your blood glucose. Castro MR expert opinion. Mayo Clinic, Rochester, Minn. July 7, Diabetic ketoacidosis and hyperosmolar hyperglycemic state in adults: Treatment. Take care of your diabetes during sick days and special times.

Accessed July 7, Classification and diagnosis of diabetes: Standards of Medical Care in Diabetes — Retinopathy, neuropathy, and foot care: Standards of Medical Care in Diabetes — Glycemic targets: Standards of Medical Care in Diabetes — Associated Procedures.

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Health Information Policy. Media Requests. News Network. Price Transparency. Medical Professionals. After the needle is inserted, a small amount of blood will be collected into a test tube or vial.

You may feel a little sting when the needle goes in or out. For some types of glucose blood tests, you will drink a sugary liquid and wait for an hour before your blood sample is taken:. If your provider orders a fasting blood glucose test or an oral glucose tolerance test, you will need to fast not eat or drink for at least eight hours before the test.

Other blood glucose tests don't require any special preparations. Ask your provider whether you need to fast before your glucose test. There is very little risk to having a blood test.

You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly. After an oral glucose tolerance test, you may feel light-headed. Your provider may suggest that you plan to have someone take you home. If your results show higher than normal glucose levels , it may mean you have or are at risk for getting diabetes.

High glucose levels may also be a sign of:. If your glucose results are not normal, it doesn't always mean you have a medical condition that needs treatment. Certain medicines and stress can affect glucose levels. To learn what your test results mean, talk with your health care provider.

Learn more about laboratory tests, reference ranges, and understanding results. If you have diabetes, you may need to do blood sugar testing at home every day to help manage your blood glucose levels.

There are two ways to do this:. The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health. Blood Glucose Test. What is a Blood Glucose Test? What is it used for?

Why do I need a blood glucose test? Symptoms of high blood glucose levels include: Increased thirst and urination peeing Blurred vision Fatigue Sores that don't heal Weight loss when you're not trying to lose weight Numbness or tingling in your feet or hands Symptoms of low blood glucose levels include: Feeling shaky or jittery Hunger Fatigue Feeling dizzy , confused, or irritable Headache A fast heartbeat or arrhythmia a problem with the rate or rhythm of your heartbeat Having trouble seeing or speaking clearly Fainting or seizures You may also need a blood glucose test if you have a high risk for developing type 2 diabetes.

You're more likely to develop diabetes if you: Are overweight or have obesity Are age 45 or older Have a family history of diabetes Have high blood pressure Don't exercise enough Have a history of heart disease or stroke Have had gestational diabetes diabetes that happens only during pregnancy If you are pregnant, you will likely get a blood glucose test between the 24th and 28th week of your pregnancy to check for gestational diabetes.

What happens during a blood glucose test? For some types of glucose blood tests, you will drink a sugary liquid and wait for an hour before your blood sample is taken: A glucose challenge test is used to test for gestational diabetes in pregnancy.

If your blood glucose level is higher than normal, you may have gestational diabetes. You'll need an oral glucose tolerance test OGTT to get a diagnosis.

An oral glucose tolerance test OGTT is used to diagnose gestational diabetes, and type 2 diabetes and prediabetes in people who aren't pregnant. A blood sample will be taken before you have a sugary drink and then again, every hour for the next 2 or 3 hours.

Will I need to do anything to prepare for the test?

If after taking this test your results are too high or too low, your diabetes care plan may need to be adjusted. When visiting your doctor, you might keep these questions in mind to ask during your appointment. If you have other questions about your numbers or your ability to manage your diabetes, make sure to work closely with your doctor or health care team.

Skip directly to site content Skip directly to search. Español Other Languages. Monitoring Your Blood Sugar.

Español Spanish Print. Minus Related Pages. Make Friends With Your Numbers. Getting an A1C Test Make sure to get an A1C test at least twice a year. Your A1C result will be reported in two ways: A1C as a percentage.

Estimated average glucose eAG , in the same kind of numbers as your day-to-day blood sugar readings. Questions To Ask Your Doctor When visiting your doctor, you might keep these questions in mind to ask during your appointment. What is my target blood sugar range? How often should I check my blood sugar?

What do these numbers mean? Are there patterns that show I need to change my diabetes treatment? What changes need to be made to my diabetes care plan? Persistent fasting hyperglycemia, for example, might indicate excessive hepatic glucose output, and patients experiencing this problem might derive benefit from using metformin Glucophage , which has been shown to decrease nocturnal hepatic glucose output.

Additionally, patients with persistent postprandial hyperglycemia might derive benefit from taking a short-acting oral agent with meals to either decrease carbohydrate absorption i.

People with type 2 diabetes who use insulin should perform SMBG at least four times per week, including at least two fasting and two postprandial values. Additional measurements at bedtime and before meals can also be obtained.

Thoughtful interpretation of SMBG data will assist patients and health care providers in selecting appropriate pharmaceutical and lifestyle regimens. There are now seven manufacturers and more than 20 types of meters available on the market. Meters vary in size, weight, test time, memory capabilities, and special features.

Most meters can measure blood glucose with only a one- or two-step process. Most also incorporate no-wipe technology, which means users do not have to wipe off excess blood after applying a blood drop to the reagent strip. In addition, many meters now require only a very small amount of blood, thus decreasing the pain of deep wounds from the lancet.

A few of the newer meters offer the option of obtaining blood samples from alternate sites, such as a forearm instead of a fingertip. This can benefit patients who find constant lancet wounds on their fingers difficult to tolerate.

Although there has been concern that the accuracy of alternate site testing is inferior to detect hypoglycemia, 4 the judicious use of this alternative may help to improve adherence to an SMBG regimen.

More complex meters have features to aid in identifying trends and to graph reports for more comprehensive data tracking, particularly for patients who test several times a day. Table 1 provides a summary of the more popular blood glucose meters.

Recent reviews of available meters have been published elsewhere. SMBG can play an important role in improving metabolic control in patients with diabetes.

It is recommended for patients treated with insulin and is desirable for all patients with diabetes. Judicious use of SMBG data can help to improve glycemic control, select an anti-diabetic regimen, and provide powerful feedback to patients wishing to improve metabolic control.

Benjamin, MD, FACP, is an assistant professor of medicine at Tufts University School of Medicine and Director of Healthcare Quality at Baystate Medical Center in Springfield, Mass.

Note of disclosure: Dr. Benjamin is a paid consultant to Becton Dickinson, which manufactures lancet devices. Sign In or Create an Account. Search Dropdown Menu. header search search input Search input auto suggest. filter your search All Content All Journals Clinical Diabetes.

Advanced Search. User Tools Dropdown. Sign In. Skip Nav Destination Close navigation menu Article navigation. Volume 20, Issue 1. Previous Article Next Article. SMBG Use and Frequency. Recommending a Meter. Article Navigation. Practical Pointer January 01 There are two ways to do this:.

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health. Blood Glucose Test.

What is a Blood Glucose Test? What is it used for? Why do I need a blood glucose test? Symptoms of high blood glucose levels include: Increased thirst and urination peeing Blurred vision Fatigue Sores that don't heal Weight loss when you're not trying to lose weight Numbness or tingling in your feet or hands Symptoms of low blood glucose levels include: Feeling shaky or jittery Hunger Fatigue Feeling dizzy , confused, or irritable Headache A fast heartbeat or arrhythmia a problem with the rate or rhythm of your heartbeat Having trouble seeing or speaking clearly Fainting or seizures You may also need a blood glucose test if you have a high risk for developing type 2 diabetes.

You're more likely to develop diabetes if you: Are overweight or have obesity Are age 45 or older Have a family history of diabetes Have high blood pressure Don't exercise enough Have a history of heart disease or stroke Have had gestational diabetes diabetes that happens only during pregnancy If you are pregnant, you will likely get a blood glucose test between the 24th and 28th week of your pregnancy to check for gestational diabetes.

What happens during a blood glucose test? For some types of glucose blood tests, you will drink a sugary liquid and wait for an hour before your blood sample is taken: A glucose challenge test is used to test for gestational diabetes in pregnancy.

If your blood glucose level is higher than normal, you may have gestational diabetes. You'll need an oral glucose tolerance test OGTT to get a diagnosis. An oral glucose tolerance test OGTT is used to diagnose gestational diabetes, and type 2 diabetes and prediabetes in people who aren't pregnant.

A blood sample will be taken before you have a sugary drink and then again, every hour for the next 2 or 3 hours. Will I need to do anything to prepare for the test? Are there any risks to the test? What do the results mean? High glucose levels may also be a sign of: Hyperthyroidism Pancreas disorders Stress from surgery, very serious illness, or trauma If you have diabetes, lower than normal glucose levels may be caused by: Side effects from certain diabetes medicines Not eating enough, especially after taking diabetes medicine Being more physically active than usual If you don't have diabetes, low blood glucose levels may be a sign of: Liver disease Kidney disease Underactive adrenal, pituitary , or thyroid gland hypothyroidism Alcohol use disorder AUD If your glucose results are not normal, it doesn't always mean you have a medical condition that needs treatment.

Is there anything else I should know about a blood glucose test? There are two ways to do this: Blood glucose meters require you to prick your finger with a small device called a lancet. You apply a drop of blood to a test strip and insert it into a small, electronic glucose meter, which measures the glucose is in your blood.

Continuous glucose monitors CGM use a tiny sensor that you insert under your skin. Every few minutes, the sensor measures glucose levels in fluids between your cells. If your glucose is too high or too low, you use a blood glucose meter to check your blood levels before making changes to raise or lower your glucose level.

References American Diabetes Association [Internet]. Arlington VA : American Diabetes Association; c— The Big Picture: Checking Your Blood Sugar [cited Apr 12]; [about 8 screens].

Gestational Diabetes; [cited Apr 12]; [about 6 screens]. Irving TX : American Pregnancy Association; c Glucose Tolerance Test; [cited Apr 12]; [about 7 screens]. Atlanta: U. Department of Health and Human Services; Basics About Diabetes; [updated Dec 16; cited Apr 12]; [about 3 screens].