When you have diabetes, monitoring your blood sugar levels is an essential part of caring for yourself. Your doctor will measure your blood sugar during regular appointments. However, since you typically have to test your blood sugar levels daily, you need to know how to monitor your own blood sugar, understand the results, and know what to do about them. It could save your life.

How Does Sugar Get into My Blood?

Glucose, or the sugar in blood, comes from the food you eat. Your digestive system breaks down food into glucose and absorbs it into your blood. Foods with carbohydrates provide most of the glucose in your diet.

Once glucose is in your blood, your cells can use it for energy. Your pancreas makes insulin when your blood sugar levels start to rise. Insulin is the hormone that helps transport glucose into the cell. If there is inadequate insulin or if cells become unresponsive to insulin, then blood glucose levels may remain abnormally high. Normally, your body keeps your blood sugar levels within a very narrow range. In diabetes, your body either can’t make insulin or your cells can’t use insulin properly, leading to high blood sugar levels.

What Tests Measure Blood Sugar?

Your doctor can measure your blood sugar with a lab test. This test looks at your blood sugar at one point in time. However, you can measure your own blood sugar with a device called a glucometer. Anyone with diabetes should have a glucometer and know how to use it correctly. They’re available without a prescription at your local pharmacy.

Your doctor can also use an A1C test to measure your blood sugar control over a period of time. This test is the best measure for long-term blood sugar control. It reflects your average blood sugar levels over the last three months.

What Are My Goal Results?

If you have diabetes, general target blood sugar levels are:

  • 70 to 130 mg/dL before a meal

  • Less than 180 mg/dL after a meal

Your goals may vary slightly depending on your circumstances. Talk to your doctor to determine goals that are right for you.

When your doctor measures A1C, the goal is a result of less than 7.

What’s Too Low?

Hypoglycemia is blood sugar levels that are too low, generally anything less than 70 mg/dL. Hypoglycemia can happen as a side effect of taking too much insulin or other diabetes medications. Severely low blood sugar levels can be dangerous. Get to know the symptoms and what to do about them.

The symptoms include:

  • Blurred vision

  • Dizziness

  • Headache

  • Hunger

  • Slurred speech

  • Sweating

  • Trembling and shakiness

  • Weakness

If you feel the symptoms of low blood sugar, test your blood sugar to verify it. To treat low blood sugar, always have an immediate source of sugar on hand. Examples include glucose tablets, hard candy with sugar, honey sticks, and fruit juice boxes.

What’s Too High?

Hyperglycemia is blood sugar levels that are too high, generally anything over 180 mg/dL. Hyperglycemia can occur when diabetes isn’t taken care of well, either with medications or diet and exercise. Severely high blood sugar can lead to a condition called diabetic ketoacidosis, coma, seizures, and death. It’s equally important to know the symptoms of high blood sugar and what to do about them. The symptoms include:

  • Blurred vision

  • Fatigue

  • Frequent urination

  • Headache

  • Increased thirst or hunger

Some of the symptoms of hyperglycemia and hypoglycemia are the same. That’s why it’s so important to test your blood sugar to verify it. Exercise and treatment changes can treat high blood sugar.

If your blood sugar levels are above 240 mg/dL, know how to check your urine for ketones. If you have ketones in your urine, do not exercise and contact your doctor immediately.

Seek immediate medical care (or dial 911) if someone with diabetes has symptoms of a serious condition, if their symptoms aren’t responding to treatment, if they don't respond appropriately or if they have passed out.

Medical Reviewer: William C. Lloyd III, MD, FACS Last Annual Review Date: Dec. 15, 2013 Copyright: © Copyright 2013 Health Grades, Inc. All rights reserved. May not be reproduced or reprinted without permission from Health Grades, Inc. Use of this information is governed by the HealthGrades User Agreement.

Your Guide to Diabetes