Blood Glucose Monitoring: What's the Right Number?

Plus, How to Choose a Blood Glucose Monitor

blood sugar testing deviceDiabetes is a marathon, not a race. Diabetes care cannot be a one-size fits all approach. (Photo: 123rd)

Measuring your glucose levels have changed over the years and have included numerous new options. Traditional blood glucose monitors are still available, but continuous glucose monitoring (CGM) has also become a mainstay in diabetes self-management, regardless of whether you have type 1 or type 2 diabetes. 

The type of monitor you choose will depend on a few things, but the most important is insurance coverage. While there are a variety of blood glucose monitors available, check with your insurance regarding which brand is covered.  Some will require a co-pay; so investigate what that co-pay will be and whether buying a blood glucose monitor over-the-counter (does not require a prescription and is usually on a shelf in the aisles surrounding a store’s pharmacy) is cheaper. 

There are also two types of continuous glucose monitors (CGMs) available: one that has alarms and alerts that will inform you of high or low glucose readings; “flash” monitoring, that requires you to “scan” the reader over the sensor attached to your body to obtain readings and alerts. 

Several of the CGM options available can also be used IN PLACE OF actual blood glucose monitoring, which means that the individual has access to their glucose readings for the entire 24 hour day. 

Another important factor when choosing a blood glucose monitor is accuracy. A recent study1 highlighted accuracy of various meters that are available. What they found is that some are not as accurate as others. According to the Food and Drug Administration (FDA)2, it is important to understand is that accuracy is determined by:

  • The quality of the meter and test strips
  • How the glucose test is performed—one should clean the hands before testing and follow the instructions for operating your meter.
  • One’s hematocrit level (the amount of red blood cells in the blood). If someone is severely dehydrated or anemic, the test results may be less accurate.
  • Interfering substances—such as vitamin C, acetominophen (Tylenol), and uric acid, may interfere with the glucose result.
  • Altitude, temperature, and humidity—high altitude, low and high temperatures (leaving a meter in a cold or hot car) and humidity can cause unpredictable glucose results.

The FDA also stated3 that in order more a glucose monitor to be approved for use in the US, the actual glucose readings need to be within a certain percentage when they test the monitors.

The specifics of those criteria are as follows and the study that compared accuracy is based on this information:

  • 95% of values must be within +/-12% for blood sugars below or above 75 mg/dL
  • 98% within +/- 15%

Setting individualized blood glucose goals is also essential to diabetes self-management and that applies to all people with diabetes. Your diabetes team will work with you to set those goals and identify ways to achieve and maintain them.  But, it is crucial to understand that this is an on-going process and goals will need to be updated regularly.

The joint position statement for diabetes self-management education and support identifies the four critical time points for diabetes self-management education: when diagnosed; at least annually; when complicating factors arise (like medication changes); and when transitions occur.

Since diabetes self-management needs change throughout the year, it is beneficial to make an appointment to see an expert who can spend quality time with you to de-construct your days, how diabetes affects it and what changes and goals would be helpful for you. Click here to find a certified diabetes educator (CDE) near you.

Blood Glucose Numbers: Expert Recommendations

There are numerous organizations that have established recommended goals for diabetes. These goals have been created, in part, to aid in reducing the risk of long-term complications caused by diabetes. 

While there are many factors that affect risk of complications, glucose control is the primary consideration in one’s everyday life.

The American Diabetes Association's4 guidelines for ideal A1C (which is a measurement of the last 3 months of blood glucose (BG) readings, averaged out) remains < or = 7 %, but this goal should be individualized based on the person. 

The ADA also recommends pre-meal BGs of <130 mg/dl and peak post-meal (1 to 2 hours after) BGs <180 mg/dl.

The ADA states that more or less stringent goals should be based on duration of diabetes, age or life expectancy, the presence of several chronic conditions, known heart or other long-term diabetes complications, hypoglycemia unawareness, and individual patient considerations (preference, social support system availability).  So, specific goals are not as black and white as we have seen them before, which means that there is no “what size fits all” goal any longer.

The American Association of Clinical Endocrinologists' (AACE)5 guidelines differ slightly than the ADA, but they have adopted the same suggestions—goals should be individualized based on the person with diabetes. A1C goals for AACE is = or <6.5%; pre-meal blood glucose goals are <110 mg/dl and a 2-hr post meal blood glucose goals are <140 mg/dl. 

What These Measures Mean in the Real World

So, what how do these number translate in your life? The measures means that diabetes care cannot be a cookie cutter approach. For the 32-year-old female with type 1 diabetes trying to get pregnant, her goals will be far more stringent than an 82-year-old male who is newly diagnosed with type 2 diabetes and has heart problems and prostate cancer. 

Both will receive individualized goals that take quality of life into account and are best for them and meet their needs. But, goals should be reviewed regularly, at least every 3-6 months, to assess if they still meet the person’s needs. If they do not, then new goals should be created.

Remember, diabetes is a marathon, not a sprint so it may take some time to reach your specific goals—there is not such thing as perfection and some days may be better than others. 

Keeping track of your blood glucose numbers and monitoring your levels as recommended by your healthcare team will help you meet your glucose goals.


Updated on: April 18, 2019
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