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How To Check Your Blood Sugar


High blood sugar levels increase your risk for heart attack, stroke, eye problems, and kidney problems. You can decrease your risk of these problems by controlling your blood sugar levels. Low blood sugar levels can also lead to serious health problems and must be treated right away. Check your blood sugar to help you learn how food, exercise, stress, and medicines affect your levels. Keep a record of your blood sugar levels. It can be used to adjust your meal plan, exercise routine, insulin doses, or diabetes medicine if needed.


Follow up with your healthcare provider or diabetes specialist as directed:

Write down your questions so you remember to ask them during your visits.

How to check your blood sugar:

  • Check your blood sugar level with a glucose meter. This device uses a small drop of blood to measure your blood sugar level. Some glucose meters take the sample from your finger with a special lancet device. Other meters use blood from your thigh, forearm, or the palm of your hand.

  • Blood sugar levels change quickly after meals, after you take insulin, during exercise, and when you feel stressed or ill. It is best to use blood from your finger to check your blood sugar level during these times. Your healthcare provider will teach you how to use a glucose meter to check your blood sugar level. Ask for more information about taking blood samples from areas other than your finger.

Steps for checking your blood sugar:

Read the instructions that came with your meter so that you understand how to use it. The following are general steps for testing your blood sugar level:

  • Wash your hands with soap and water.

  • Place a test strip into the blood glucose meter.

  • Choose a spot on the side of your fingertip and poke it with the lancet device. Wait for a drop of blood to form. If a drop does not form, gently squeeze your finger until a drop forms.

  • Place the drop of blood on or near the test area of the test strip. Wait until the right amount of blood has been drawn into the test strip.

  • Use gauze or a tissue to clean your fingertip. Keep it on the area until the bleeding has stopped.

  • Write down your blood sugar level.

  • Throw away the lancet in a hard container with a lid. Keep the container out of the reach of children and pets.

When and how often should you check your blood sugar level:

Ask your healthcare provider when and how often you should check your blood sugar levels. Check your blood sugar at least 3 times each day if you use an insulin pump or need several injections of insulin each day. Your healthcare provider may suggest that your blood sugar level should be between 70 mg/dL and 130 mg/dL before meals. Your blood sugar level may need to be less than 180 mg/dL after meals. Blood sugar levels need to be checked more often when you are sick, or if you change your daily routine. Test your blood sugar if you feel like your blood sugar may be too high (hyperglycemia) or too low (hypoglycemia).

Signs and symptoms of hyperglycemia:

Check your blood sugar level if you have any of the following signs and symptoms:

  • More thirst than usual

  • More urine than usual

  • More hunger than usual

  • Blurred vision

Signs and symptoms of hypoglycemia:

If your blood glucose level is low, you need to eat some sugar right away. Ask your healthcare provider for more information about how to treat hypoglycemia. Check your blood sugar level if you have any of the following signs and symptoms:

  • Fast heartbeat

  • Feeling dizzy, lightheaded, shaky, or confused

  • Headache

  • Sweating

Keep a record of your blood sugar levels:

Write down your blood sugar level each time you test it. Write down the date, the time of the test (including if it was before or after a meal), and the result. Write down the time you took your insulin or diabetes pills. Record the type and amount of insulin or diabetes medicine you took. Write comments about anything that may have made your blood sugar level go up or down. Your blood sugar level can be affected by exercise, eating more or less than usual, or stress. Bring this record with you every time you see your healthcare provider.

How to care for your glucose meter and test strips:

  • Storage: Keep the test strips away from heat, cold, and moisture. Do not take a test strip out of the container until you are ready to use it. Put the lid back tightly on the container. Do not use test strips that are damaged, wet, or bent.

  • Expiration date: Check the date on the test strip container to be sure the test strips have not expired. Your blood sugar readings may be wrong if you use expired test strips. Use only the type of glucose test strips that work with your glucose meter.

  • Coding your meter: Your meter may need a special code that matches each new bottle of test strips you use. If your meter is not coded correctly, your blood sugar readings may be wrong. Follow the instructions for entering the code that came with your meter or strips.

  • Accuracy: Check the accuracy of your meter by testing a drop of control solution. Control solution often comes with a meter or can be bought at drug or medical supply stores. The blood sugar reading of the control solution should match the one that is listed on the bottle.

Medical alert identification:

Wear medical alert jewelry or carry a card that says you have diabetes. Your healthcare provider can tell you where to get these items.

Contact your healthcare provider or diabetes specialist if:

  • You often have high or low blood sugar levels.

  • You have a fever.

  • You have questions or concerns about your condition or care.

Return to the emergency department if:

  • You are vomiting.

  • You cannot think clearly or are very weak, sweating, or pale.

  • You are breathing faster or slower than normal, are very sleepy, or your breath smells fruity.

  • You have chest pain.

  • You pass out.

  • You have a seizure.

© 2015 Truven Health Analytics Inc. Information is for End User's use only and may not be sold, redistributed or otherwise used for commercial purposes. All illustrations and images included in CareNotes® are the copyrighted property of A.D.A.M., Inc. or Truven Health Analytics.

The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.