BACK TOTOP Browse A-ZSearchBrowse A-ZABCDEFGHIJKLMNOPQRSTUVWXYZ0-9 E-mail FormEmail ResultsName:Email address:Recipients Name:Recipients address:Message: Print-FriendlyBookmarksbookmarks-menuBlood sugar testRandom blood sugar; Blood sugar level; Fasting blood sugar; Glucose test; Diabetic screening - blood sugar test; Diabetes - blood sugar testA blood sugar test measures the amount of a sugar called glucose in a sample of your blood.Glucose is a major source of energy for most cells of the body, including brain cells. Glucose is a building block for carbohydrates. Carbohydrates are found in fruit, cereal, bread, pasta, and rice. Carbohydrates are quickly turned into glucose in your body. This can raise your blood glucose level.Hormones made in the body help control blood glucose level. How the Test is Performed A blood sample is needed. How to Prepare for the Test The test may be done in the following ways: After you have not eaten anything for at least 8 hours (fasting) At any time of the day (random) Two hours after you drink a certain amount of glucose (oral glucose tolerance test) Oral glucose tolerance testThe glucose tolerance test is a lab test to check how your body moves sugar from the blood into tissues like muscle and fat. The test is often used ...ImageRead Article Now Book Mark Article How the Test will Feel When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or slight bruising. This soon goes away. Why the Test is Performed Your health care provider may order this test if you have signs of diabetes. More than likely, the provider will order a fasting blood sugar test.DiabetesDiabetes is a long-term (chronic) disease in which the body cannot regulate the amount of sugar in the blood.ImageRead Article Now Book Mark Article The blood glucose test is also used to monitor people who already have diabetes. The test may also be done if you have:An increase in how often you need to urinate Recently gained a lot of weight Blurred vision Confusion or a change in the way you normally talk or behave Fainting spells Seizures (for the first time) Unconsciousness or comaSCREENING FOR DIABETESThis test may also be used to screen a person for diabetes.High blood sugar and diabetes may not cause symptoms in the early stages. A fasting blood sugar test is almost always done to screen for diabetes.If you are over age 45 and have no diabetes risk factors, you should be tested every 3 years.If you're overweight or obese (body mass index, or BMI, of 25 or higher), you should be screened for prediabetes or type 2 diabetes starting at age 35.If you're overweight and have any of the other risk factors below, ask your provider about getting tested at an earlier age and more often:High blood sugar level on a previous test Blood pressure of 140/90 mm Hg or higher, or unhealthy cholesterol levels History of heart disease Member of a high-risk ethnic group (African American, Latino, Native American, Asian American, or Pacific Islander) Woman who has been previously diagnosed with gestational diabetes Polycystic ovary disease (condition in which a woman has an imbalance of female sex hormones causing cysts in the ovaries) Close relative with diabetes (such as a parent, brother, or sister) Not physically active Children age 10 and older who are overweight and have at least two of the risk factors listed above should be tested for type 2 diabetes every 3 years, even if they have no symptoms. Normal Results If you had a fasting blood glucose test, a level between 70 and 100 mg/dL (3.9 and 5.6 mmol/L) is considered normal.If you had a random blood glucose test, a normal result depends on when you last ate. Most of the time, the blood glucose level will be 125 mg/dL (6.9 mmol/L) or lower.The examples above show the common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or may test different specimens. Talk to your provider about the meaning of your specific test results.Blood glucose measured by a blood test from a vein is considered more accurate than blood glucose measured from a fingerstick with a blood glucose meter, or blood glucose measured by a continuous glucose monitor. What Abnormal Results Mean If you had a fasting blood glucose test: A level of 100 to 125 mg/dL (5.6 to 6.9 mmol/L) means you have impaired fasting glucose, a type of prediabetes. This increases your risk of developing type 2 diabetes. A level of 126 mg/dL (7 mmol/L) or higher usually means you have diabetes. If you had a random blood glucose test:A level of 200 mg/dL (11 mmol/L) or higher often means you have diabetes. Your provider will order a fasting blood glucose, A1C test, or glucose tolerance test, depending on your random blood glucose test result. A1C testA1C is a lab test that shows the average level of blood sugar (glucose) over the previous 3 months. It shows how well you are controlling your blood...ImageRead Article Now Book Mark Article Glucose tolerance testThe glucose tolerance test is a lab test to check how your body moves sugar from the blood into tissues like muscle and fat. The test is often used ...ImageRead Article Now Book Mark Article In someone who has diabetes, an abnormal result on the random blood glucose test may mean that the diabetes is not well controlled. Talk with your provider about your blood glucose goals if you have diabetes.Other medical problems can also cause a higher-than-normal blood glucose level, including:Overactive thyroid gland Overactive thyroid glandHyperthyroidism is a condition in which the thyroid gland makes too much thyroid hormone. The condition is often called overactive thyroid.ImageRead Article Now Book Mark Article Pancreatic cancer Pancreatic cancerPancreatic cancer is cancer that starts in the pancreas.ImageRead Article Now Book Mark Article Swelling and inflammation of the pancreas (pancreatitis) PancreatitisAcute pancreatitis is sudden swelling and inflammation of the pancreas.ImageRead Article Now Book Mark Article Stress due to trauma, stroke, heart attack, or surgery Rare tumors, including pheochromocytoma, acromegaly, Cushing syndrome, or glucagonomaPheochromocytomaPheochromocytoma is a rare tumor of adrenal gland tissue. It results in the release of too much epinephrine and norepinephrine, hormones that contro...ImageRead Article Now Book Mark Article AcromegalyAcromegaly is a condition in which there is too much growth hormone (GH) in the body.ImageRead Article Now Book Mark Article Cushing syndromeCushing syndrome is a disorder that occurs when your body has a high level of the hormone cortisol.ImageRead Article Now Book Mark Article GlucagonomaGlucagonoma is a very rare tumor of the islet cells of the pancreas, which leads to an excess of the hormone glucagon in the blood.ImageRead Article Now Book Mark Article A lower-than-normal blood glucose level (hypoglycemia) may be due to:HypoglycemiaLow blood sugar is a condition that occurs when the body's blood sugar (glucose) decreases and is too low. Blood sugar below 70 mg/dL (3. 9 mmol/L) i...ImageRead Article Now Book Mark Article Hypopituitarism (a pituitary gland disorder) HypopituitarismHypopituitarism is a condition in which the pituitary gland does not produce normal amounts of some or all of its hormones.ImageRead Article Now Book Mark Article Underactive thyroid gland or adrenal gland Underactive thyroid glandHypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone. This condition is often called underactive thyroid....ImageRead Article Now Book Mark Article Tumor in the pancreas (insulinoma - very rare) InsulinomaAn insulinoma is a tumor in the pancreas that produces too much insulin.ImageRead Article Now Book Mark Article Too little food Too much insulin or other diabetes medicines Liver or kidney disease Weight loss after weight loss surgery Vigorous exercise Some medicines can raise or lower your blood glucose level. Before having the test, tell your provider about all the medicines you are taking.For some thin young women, a fasting blood sugar level below 70 mg/dL (3.9 mmol/L) may be normal. Risks There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.Other risks associated with having blood drawn are slight, but may include:Excessive bleeding Fainting or feeling lightheaded Multiple punctures to locate veins Hematoma (blood accumulating under the skin) Infection (a slight risk any time the skin is broken)Open ReferencesReferencesAmerican Diabetes Association. 2. Classification and Diagnosis of Diabetes: Standards of Medical Care in Diabetes-2021. Diabetes Care. 2021 Jan;44(Suppl 1):S15-S33. PMID: 33298413 pubmed.ncbi.nlm.nih.gov/33298413/.Chernecky CC, Berger BJ. Glucose, 2-hour postprandial - serum norm. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ed. St Louis, MO: Elsevier Saunders; 2013:585.Chernecky CC, Berger BJ. Glucose tolerance test (GTT, OGTT) - blood norm. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ed. St Louis, MO: Elsevier Saunders; 2013:591-593.US Preventive Services Task Force, Davidson KW, Barry MJ, Mangione CM, et al. Screening for prediabetes and type 2 diabetes: US Preventive Services Task Force recommendation statement. JAMA. 2021;326(8):736-743. PMID: 34427594 pubmed.ncbi.nlm.nih.gov/34427594/.AllVideoImagesTogBlood test - illustration Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.Blood testillustrationBlood test - illustration Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.Blood testillustrationA Closer Look High blood pressure(Alt. Medicine)High blood pressure(In-Depth)Diabetes - type 2(In-Depth)Diabetes - type 1(In-Depth)Diabetes(Alt. Medicine)Talking to your MD Type 2 diabetes - what to ask your doctorSelf Care Home blood sugar testingManaging your blood sugarPre-existing diabetes and pregnancyGestational diabetes - self-careLong-term complications of diabetesDiabetes - when you are sickPrediabetesPrenatal care in your first trimesterDiabetes tests and checkupsPrenatal care in your second trimester Tests for Blood sugar test Blood sugar testGlucagon blood testSugar-water hemolysis testGlucose screening tests during pregnancyGlucose urine testGlucose tolerance test - non-pregnantGrowth hormone suppression testKetones blood testPyruvate kinase blood testA1C testRelated Information Diabetes(Condition)Carbohydrates(Nutrition)Confusion(Symptoms)Unconsciousness - first aid(Injury)Glucagon blood test(Medical Test)Type 1 diabetes(Condition)Acromegaly(Condition)Cushing syndrome(Condition)Hyperthyroidism(Condition)Pancreatic cancer(Condition)Type 2 diabetes - what to ask your doctor(Doctor Questions)Diabetes - type 1(In-Depth)Hypothyroidism(In-Depth)Alzheimer disease(In-Depth) Review Date: 1/26/2020 Reviewed By: Brent Wisse, MD, board certified in Metabolism/Endocrinology, Seattle, WA. Internal review and update on 06/03/2021 by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. Editorial update 09/03/2021. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- © 1997- All rights reserved. A.D.A.M. content is best viewed in IE9 or above, Firefox and Google Chrome browser.Content is best viewed in IE9 or above, Firefox and Google Chrome browser.