What is a high sugar level number

Blood glucose that gets too high or too low can be dangerous. To stay safe and healthy, check your blood glucose regularly and watch for certain symptoms, like being very hungry, tired or sleepy. If your blood glucose is outside the normal range, take the steps described below to start feeling better.

High Blood Glucose: Hyperglycemia

Hyperglycemia means that you have too much blood glucose. It happens when your blood glucose level is around 200 mg/dL or higher. Hyperglycemia can happen if you miss taking your diabetes medications, eat too much or do not get enough exercise. Sometimes, the medications you take for other problems cause high blood glucose.

Symptoms of hyperglycemia include:

  • Being very thirsty
  • Being very tired
  • Having blurry vision
  • Having to urinate often

If you have these symptoms, check your blood glucose right away. If it’s too high, follow these steps:

  • Check your blood glucose every four hours. If your level does not go down after two checks or your symptoms get worse, call a member of your diabetes team.
  • Drink water or other sugar-free liquids, such as diet soda or Crystal Light.
  • You may need to take an extra dose of insulin. Your diabetes educator talks with you more about this.

High Blood Glucose: Diabetic Ketoacidosis (DKA)

If your insulin level is too low, your blood glucose could become so high that it is unsafe. You might develop a serious problem called diabetic ketoacidosis (or DKA). This usually happens in people with Type 1 diabetes and those with glucose levels over 500.

If you have DKA, chemicals called ketones start to make a lot of acid in your body. The acid and high blood glucose can make you very sick. You might also become dehydrated (lose body fluid). You can prevent DKA by carefully giving yourself the correct insulin dose every day.

If you have any of the following symptoms of DKA, get to your local emergency department right away. You need to be treated with insulin and fluids that are given to you through an IV (a thin tube placed in your arm):

  • Blurry vision
  • Decreased appetite
  • Dry mouth, eyes or skin
  • Fast breathing
  • Feeling confused or irritable
  • Feeling very weak or tired
  • Fruity-smelling breath
  • Stomach pain, nausea or vomiting

Low Blood Glucose: Hypoglycemia

Hypoglycemia can occur when blood glucose drops below normal levels or drops too quickly. Your blood glucose level is too low if it is under 70 mg/dL.

Hypoglycemia can be caused by:

  • A combination of these factors
  • Being more active than usual
  • Drinking alcohol
  • Eating at the wrong time for the medications you take
  • Skipping or not finishing meals or snacks
  • Taking too much diabetes medication

You can have hypoglycemia without any symptoms. That makes it important to check your blood glucose levels regularly. When hypoglycemia does cause symptoms, they can include:

  • Being sweaty
  • Fast heartbeat
  • Feeling irritable
  • Feeling shaky
  • Feeling tired
  • Headache
  • Hunger

If you have these symptoms, check your blood glucose right away. If it is too low (under 70 mg/dL), take something with sugar right away. This quickly raises your blood glucose level. Some good options include:

  • Five to six hard candies
  • One-half cup (4 oz) of fruit juice or regular soda
  • Three glucose tablets

You should also check your blood glucose again after 15 minutes. If it’s still low, again take something with sugar. Check your blood glucose level again after another 15 minutes. If it is still low, call a member of your diabetes team. If your next meal is more than an hour away, eat a small snack.


*The content on this website is for informational purposes only and is not medical advice. Please consult a physician regarding your specific medical condition, diagnosis and/or treatment.

You’ll need to get your blood sugar tested to find out for sure if you have prediabetes or type 1, type 2, or gestational diabetes. Testing is simple, and results are usually available quickly.

Tests for Type 1 Diabetes, Type 2 Diabetes, and Prediabetes

Your doctor will have you take one or more of the following blood tests to confirm the diagnosis:

A1C Test

The A1C test measures your average blood sugar level over the past 2 or 3 months. An A1C below 5.7% is normal, between 5.7 and 6.4% indicates you have prediabetes, and 6.5% or higher indicates you have diabetes.

Fasting Blood Sugar Test

This measures your blood sugar after an overnight fast (not eating). A fasting blood sugar level of 99 mg/dL or lower is normal, 100 to 125 mg/dL indicates you have prediabetes, and 126 mg/dL or higher indicates you have diabetes.

Glucose Tolerance Test

This measures your blood sugar before and after you drink a liquid that contains glucose. You’ll fast (not eat) overnight before the test and have your blood drawn to determine your fasting blood sugar level. Then you’ll drink the liquid and have your blood sugar level checked 1 hour, 2 hours, and possibly 3 hours afterward. At 2 hours, a blood sugar level of 140 mg/dL or lower is considered normal, 140 to 199 mg/dL indicates you have prediabetes, and 200 mg/dL or higher indicates you have diabetes.

Random Blood Sugar Test

This measures your blood sugar at the time you’re tested. You can take this test at any time and don’t need to fast (not eat) first. A blood sugar level of 200 mg/dL or higher indicates you have diabetes.

Random Blood Sugar Test
Result*A1C TestFasting Blood Sugar TestGlucose Tolerance TestRandom Blood Sugar Test
Diabetes6.5% or above 126 mg/dL or above 200 mg/dL or above 200 mg/dL or above
Prediabetes5.7 – 6.4% 100 – 125 mg/dL 140 – 199 mg/dL  N/A
NormalBelow 5.7% 99 mg/dL or below 140 mg/dL or below  N/A

*Results for gestational diabetes can differ. Ask your health care provider what your results mean if you’re being tested for gestational diabetes.
Source: American Diabetes Association

If your doctor thinks you have type 1 diabetes, your blood may also tested for autoantibodies (substances that indicate your body is attacking itself) that are often present in type 1 diabetes but not in type 2 diabetes. You may have your urine tested for ketones (produced when your body burns fat for energy), which also indicate type 1 diabetes instead of type 2 diabetes.

Tests for Gestational Diabetes

Gestational diabetes is diagnosed using blood tests. You’ll probably be tested between 24 and 28 weeks of pregnancy. If your risk is higher for getting gestational diabetes (due to having more risk factors), your doctor may test you earlier. Blood sugar that’s higher than normal early in your pregnancy may indicate you have type 1 or type 2 diabetes rather than gestational diabetes.

Glucose Screening Test

This measures your blood sugar at the time you’re tested. You’ll drink a liquid that contains glucose, and then 1 hour later your blood will be drawn to check your blood sugar level. A normal result is 140 mg/dL or lower. If your level is higher than 140 mg/dL, you’ll need to take a glucose tolerance test.

Glucose Tolerance Test

This measures your blood sugar before and after you drink a liquid that contains glucose. You’ll fast (not eat) overnight before the test and have your blood drawn to determine your fasting blood sugar level. Then you’ll drink the liquid and have your blood sugar level checked 1 hour, 2 hours, and possibly 3 hours afterward. Results can differ depending on the size of the glucose drink and how often your blood sugar is tested. Ask your doctor what your test results mean.

Prevent Type 2 Diabetes

If your test results show you have prediabetes, ask your doctor or nurse if there is a lifestyle change program offered through the CDC-led National Diabetes Prevention Program in your community. You can also search for an online or in-person program. Having prediabetes puts you at greater risk for developing type 2 diabetes, but participating in the program can lower your risk by as much as 58% (71% if you’re over age 60).

Diabetes Treatment Plan

If your test results show you have type 1, type 2, or gestational diabetes, talk with your doctor or nurse about a detailed treatment plan—including diabetes self-management education and support services—and specific steps you can take to be your healthiest.