What Is the Normal Range for Blood Sugar? - MedicineNet

Ask a Doctor

I've just been diagnosed with diabetes and there's so much information, my mind is reeling. I know insulin levels and blood sugar levels are important to monitor, but I know little about the process. For example, what is the normal range for blood sugar?

Doctor’s Response

One important goal of diabetes treatment is to keep the blood glucose levels near the normal range of 70 to 120 mg/dl before meals and under 140 mg/dl at two hours after eating.

Home blood sugar (glucose) testing is an important part of controlling blood sugar. Blood glucose levels are usually tested before and after meals, and at bedtime. The blood sugar level is typically determined by pricking a fingertip with a lancing device and applying the blood to a glucose meter, which reads the value. There are many meters on the market, for example, Accu-Check Advantage, One Touch Ultra, Sure Step and Freestyle. Each meter has its own advantages and disadvantages (some use less blood, some have a larger digital readout, some take a shorter time to give you results, etc.). The test results are then used to help patients make adjustments in medications, diets, and physical activities.

There are some interesting developments in blood glucose monitoring including continuous glucose sensors. The new continuous glucose sensor systems involve an implantable cannula placed just under the skin in the abdomen or in the arm. This cannula allows for frequent sampling of blood glucose levels. Attached to this is a transmitter that sends the data to a pager-like device. This device has a visual screen that allows the wearer to see, not only the current glucose reading, but also the graphic trends. In some devices, the rate of change of blood sugar is also shown. There are alarms for low and high sugar levels. Certain models will alarm if the rate of change indicates the wearer is at risk for dropping or rising blood glucose too rapidly. One version is specifically designed to interface with their insulin pumps. In most cases the patient still must manually approve any insulin dose (the pump cannot blindly respond to the glucose information it receives, it can only give a calculated suggestion as to whether the wearer should give insulin, and if so, how much). However, in 2013 the US FDA approved the first artificial pancreas type device, meaning an implanted sensor and pump combination that stops insulin delivery when glucose levels reach a certain low point. All of these devices need to be correlated to fingersticks measurements for a few hours before they can function independently. The devices can then provide readings for 3 to 5 days.

Diabetes experts feel that these blood glucose monitoring devices give patients a significant amount of independence to manage their disease process; and they are a great tool for education as well. It is also important to remember that these devices can be used intermittently with fingerstick measurements. For example, a well-controlled patient with diabetes can rely on fingerstick glucose checks a few times a day and do well. If they become ill, if they decide to embark on a new exercise regimen, if they change their diet and so on, they can use the sensor to supplement their fingerstick regimen, providing more information on how they are responding to new lifestyle changes or stressors. This kind of system takes us one step closer to closing the loop, and to the development of an artificial pancreas that senses insulin requirements based on glucose levels and the body's needs and releases insulin accordingly - the ultimate goal.

Hemoglobin A1c (HBA1c)

To explain what hemoglobin A1c is, think in simple terms. Sugar sticks, and when it's around for a long time, it's harder to get it off. In the body, sugar sticks too, particularly to proteins. The red blood cells that circulate in the body live for about three months before they die off. When sugar sticks to these hemoglobin proteins in these cells, it is known as glycosylated hemoglobin or hemoglobin A1c (HBA1c). Measurement of HBA1c gives us an idea of how much sugar is present in the bloodstream for the preceding three months. In most labs, the normal range is 4%-5.9 %. In poorly controlled diabetes, its 8.0% or above, and in well controlled patients it's less than 7.0% (optimal is <6.5%). The benefits of measuring A1c is that is gives a more reasonable and stable view of what's happening over the course of time (three months), and the value does not vary as much as finger stick blood sugar measurements. There is a direct correlation between A1c levels and average blood sugar levels as follows.

While there are no guidelines to use A1c as a screening tool, it gives a physician a good idea that someone is diabetic if the value is elevated. Right now, it is used as a standard tool to determine blood sugar control in patients known to have diabetes.

HBA1c(%)Mean blood sugar (mg/dl)6135717082059240102751131012345

Checking your blood glucose, also known as Self-Monitoring of Blood Glucose (SMBG) or Blood Glucose Monitoring (BGM), is a method of checking how much glucose (or sugar) is in your blood using a blood glucose meter. Your doctor may also test your glucose from a blood sample that is checked in the lab.

 

Blood glucose targets for many non-pregnant adults*
 

Before meal

80-130 mg/dL

After meal

Less than 180 mg/dL

Your doctor uses a lab test called an A1C (also known as HbA1C or Glycosylated Hemoglobin) test to see what your average blood glucose level has been over the most recent 2-3 months. This lab test gives you and your doctor an indication of how well you are responding to your treatment plan. The recommended goal for many non-pregnant adults with diabetes is to keep the A1C level below seven percent (7%). Your doctor can talk to you about the goal that is right for you. Children, pregnant women, and older individuals will have specific targets to be recommended by their physicians or healthcare professionals.

Another way you and your doctor may monitor your progress is to follow the percent of glucose readings that fall within your target range. A1C values and complications of diabetes also track well with the readings in range, which you can see on certain blood glucose meters.

 

The importance of self-monitoring
 

While your A1C lab test result reflects your average blood glucose over a period of time, it cannot show the effects of specific food choices and activities on your daily blood glucose levels. Using a blood glucose meter is a good way for you to check and track the immediate effects of food, activities and other conditions on your blood glucose levels. This allows you to take actions as needed to bring your glucose levels within the range recommended by your doctor. Your doctor may use your blood glucose meter results, in addition to your A1C lab test result, to assess and adjust your treatment plan.

When to check and what it can tell you – a practical guide
 

Your doctor or healthcare provider will recommend how often and when to check, but you can use this simple chart to help you understand some helpful times to check and what to observe when managing your blood glucose levels on a daily basis.

 

When to check

What it can tell you

First thing in the morning, before you eat or drink

How your blood glucose reacts to food/medication overnight

Before meals

How your diabetes medicine dose is working between meals
If you might need to adjust your food choices (carbohydrates) and portion(s) for the upcoming meal or activities

1-2 hours after meals

How food and/or medicine affected your blood glucose levels

Before physical activity

If you might need to delay or postpone exercise
If you might need to have a snack before you begin exercise

During and after physical activity

How physical activity affects your blood glucose
Whether your activity has any delayed effect on your blood glucose

Before going to bed

Whether you need a snack before bedtime or possibly an insulin correction

Before driving

Whether you need to delay driving and first take action to correct your blood glucose in order to drive safely

You may need to check your blood glucose more often when:

• you have experienced hypoglycemia (low blood glucose) or hyperglycemia (high blood glucose)
• you start taking new diabetes medicine(s)
• your diabetes medicine dose is adjusted
• you are traveling or visiting a location in a different time zone
• you try new foods
• you are sick or don’t feel well

Always check with your doctor to find out when and how often you need to check your blood glucose especially if there is a change in your health or medical condition.

 

Recording your blood glucose results
 

• You can keep a logbook handy or use an app like OneTouch Reveal® where you can record your blood glucose readings.
• You can find logbooks at your doctor’s office, healthcare centers, and even online. (Download one here.)
• Always update your blood glucose records and take them with you to your doctor visits. Your diabetes care team can use them when determining the proper treatment plan for you.
   

Source:
 

Glycemic Targets: Standards of Medical Care in Diabetes. 2022;45(Suppl. 1):S66-S76. Last accessed June 22, 2022.
Mayo Clinic. Blood Sugar Testing: Why, When, and How. Last accessed online May 6, 2022