What are high glucose levels in blood

Hyperglycemia is the technical term for high blood glucose (blood sugar). High blood glucose happens when the body has too little insulin or when the body can't use insulin properly.

What causes hyperglycemia?

A number of things can cause hyperglycemia:

• If you have type 1, you may not have given yourself enough insulin.
• If you have type 2, your body may have enough insulin, but it is not as effective as it should be.
• You ate more than planned or exercised less than planned.
• You have stress from an illness, such as a cold or flu.
• You have other stress, such as family conflicts or school or dating problems.
• You may have experienced the dawn phenomenon (a surge of hormones that the body produces daily around 4:00 a.m. to 5:00 a.m.).

What are the symptoms of hyperglycemia?

The signs and symptoms include the following:

• High blood glucose
• High levels of glucose in the urine
• Frequent urination
• Increased thirst

Part of managing your diabetes is checking your blood glucose often. Ask your doctor how often you should check and what your glucose sugar levels should be. Checking your blood and then treating high blood glucose early will help you avoid problems associated with hyperglycemia.

How do I treat hyperglycemia?

You can often lower your blood glucose level by exercising. However, if your blood glucose is above 240 mg/dl, check your urine for ketones. If you have ketones, do not exercise.

Exercising when ketones are present may make your blood glucose level go even higher. You'll need to work with your doctor to find the safest way for you to lower your blood glucose level.

Cutting down on the amount of food you eat might also help. Work with your dietitian to make changes in your meal plan. If exercise and changes in your diet don't work, your doctor may change the amount of your medication or insulin or possibly the timing of when you take it.

What if it goes untreated?

Hyperglycemia can be a serious problem if you don't treat it, so it's important to treat as soon as you detect it. If you fail to treat hyperglycemia, a condition called ketoacidosis (diabetic coma) could occur. Ketoacidosis develops when your body doesn't have enough insulin. Without insulin, your body can't use glucose for fuel, so your body breaks down fats to use for energy.

When your body breaks down fats, waste products called ketones are produced. Your body cannot tolerate large amounts of ketones and will try to get rid of them through the urine. Unfortunately, the body cannot release all the ketones and they build up in your blood, which can lead to ketoacidosis.

Ketoacidosis is life-threatening and needs immediate treatment. Symptoms include:

• Shortness of breath
• Breath that smells fruity
• Nausea and vomiting
• Very dry mouth

Talk to your doctor about how to handle this condition.

Medical IDs

Many people with diabetes, particularly those who use insulin, should have a medical ID with them at all times.

In the event of a severe hypoglycemic episode, a car accident, or other emergency, the medical ID can provide critical information about the person's health status, such as the fact that they have diabetes, whether or not they use insulin, whether they have any allergies, etc. Emergency medical personnel are trained to look for a medical ID when they are caring for someone who can't speak for themselves.

Medical IDs are usually worn as a bracelet or a necklace. Traditional IDs are etched with basic, key health information about the person, and some IDs now include compact USB drives that can carry a person's full medical record for use in an emergency.

How can I prevent hyperglycemia?

Your best bet is to practice good diabetes management and learn to detect hyperglycemia so you can treat it early—before it gets worse.

If you're new to type 2 diabetes, join our free Living With Type 2 Diabetes program to get help and support during your first year.

What is a Blood Glucose Test?

A blood glucose test measures the glucose levels in your blood. Glucose is a type of sugar. It is your body's main source of energy. A hormone called insulin helps move glucose from your bloodstream into your cells.

Too much or too little glucose in the blood can be a sign of a serious medical condition. High blood glucose levels (hyperglycemia) may be a sign of diabetes, a disorder that can cause serious, long-term health conditions.

High blood sugar may also be caused by other conditions that can affect insulin or glucose levels in your blood, such as problems with your pancreas or adrenal glands.

Low blood glucose levels (hypoglycemia) are common among people with type 1 diabetes and people with type 2 diabetes who take certain diabetes medicines. Certain conditions, such as liver disease, may cause low levels of blood glucose in people without diabetes, but this is uncommon. Without treatment, severe low blood sugar can lead to major health problems, including seizures and brain damage.

Other names: blood sugar, self-monitoring of blood glucose (SMBG), fasting plasma glucose (FPG), fasting blood sugar (FBS), fasting blood glucose (FBG), random blood sugar, glucose challenge test, oral glucose tolerance test (OGTT)

What is it used for?

A blood glucose test is used to find out if your blood sugar levels are in a healthy range. It is often used to help diagnose and monitor diabetes.

Why do I need a blood glucose test?

Your health care provider may order a blood glucose test if you have symptoms of high glucose levels or low glucose levels.

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?

A health care professional will take a blood sample from a vein in your arm, using a small needle. 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:

• 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 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.

Are there any risks to the 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.

What do the results mean?

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:

• 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. 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.

Is there anything else I should know about a blood glucose test?

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:

• 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.

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What is considered a high glucose level?

What happens if glucose levels are high?