Blood Glucose Monitoring

Blood glucose monitoring helps to identify patterns in the fluctuation of blood glucose (sugar) levels that occur in response to diet, exercise, medications, and pathological processes associated with blood glucose fluctuations, such as diabetes mellitus. Unusually high or low blood glucose levels can potentially lead to life-threatening conditions, both acute and chronic. Blood glucose level (BGL) or blood sugar level (BSL) monitoring conducted outside of clinical facilities, such as the home, are often referred to as capillary blood glucose (CBG) tests. In contrast, blood glucose tests performed at clinical facilities may include CBG and plasma glucose venous blood tests.

Monitoring your blood sugar (glucose) is key to finding out how well your current treatment plan is working. The results of blood sugar monitoring can help you make decisions about food, physical activity and dosing insulin.

There are several things can affect your blood sugar. For example, the following situations typically raise blood sugar levels:

• Consuming carbohydrates.
• Not taking enough diabetes medication or insulin or missing a dose.
• Consistent lack of exercise or getting less activity than you usually do.

The following situations typically lower your blood sugar:

• Missing meals.
• Taking too much diabetes medication or insulin.
• Physical activity.

The following situations can raise and/or lower your blood sugar depending on other factors and your unique biology:

• Periods (menstruation).
• Food and medication/insulin timing.
• Drinking beverages containing alcohol.
• Non-diabetes medication interactions.

Due to all of these varying factors, it's essential to monitor your blood sugar if you have diabetes. It's the only way to know for sure when your blood sugar levels are changing.

Blood sugar monitoring for people offers undeniable health benefits
For people with diabetes, a major goal of therapy is to keep the blood sugar close to the normal range. This helps to prevent symptoms and complications, prolong life, and improve quality of life.

If knowledge is power, why not monitor your blood sugar?
So, why would a person who doesn't have diabetes want to monitor their blood sugar? Possible reasons include :
Detecting prediabetes. In prediabetes blood sugar is slightly high, but not high enough to meet the definition of diabetes. For healthy people, blood sugar testing is typically recommended every three years or so; if prediabetes is diagnosed, repeat testing is recommended more often, at least yearly. CGM might allow earlier diagnosis of prediabetes or diabetes. This could be particularly helpful for people at higher risk for diabetes due to family history or other factors, and people taking medicines that can raise blood sugar.

The notion of "optimizing" blood sugar for peak mental or physical performance. Not surprisingly, knowing your blood sugar can help you make changes to keep it in an "ideal range" that will help you perform your best, prevent diabetes, or improve health in some other way. For example, you might change what or when you eat. Having more information about your body may provide you with a sense of control over your health, even if you take no immediate action.

Glucose monitoring can be done in two ways, blood glucose monitoring (BGM) and continuous glucose monitoring (CGM).

Blood glucose monitoring — BGM requires fingersticks to get small samples of blood. The glucose level in the blood sample is measured with a glucose meter. The detailed steps for checking blood glucose through BGM are described below. 

Continuous glucose monitoring — CGM systems use a sensor to measure the level of glucose in the fluid under the skin. The sensor is attached to a transmitter placed on your skin, which is held in place with a sticky patch.

It wirelessly transmits results to a small recording device (no larger than a cell phone) or to a smartphone or other smart device. In some cases, it transmits the information directly to an insulin pump. You can attach the recording device to your clothing, carry it in a purse or bag, or place it near you (eg, on a bedside table).

If you use a CGM system, you will need to remove the sensor and replace it on a different part of your body approximately once every 7 to 14 days. Different CGM systems are available; one implantable sensor can last up to 180 days, but it needs to be inserted and removed by a physician, nurse practitioner, or physician assistant.

Studies have proven that people with diabetes who maintain normal or near-normal blood glucose levels reduce their risk of diabetes-related complications. Checking your glucose levels can play an important role in achieving your glucose goals and reducing the risk of complications. 

• How often you need to check your glucose will depend upon:
  The type of diabetes you have (type 1 or 2)
• Which treatment(s) you use (oral medications, insulin, non-insulin injectable medications, and/or lifestyle changes)
• Your treatment goals

Type 1 diabetes — For people with type 1 diabetes, frequent glucose testing is the only way to safely and effectively manage blood glucose levels. People with type 1 diabetes may use blood glucose monitoring (BGM) with fingersticks and a glucose meter, or continuous glucose monitoring (CGM). In people with type 1 diabetes, CGM is generally used if available and affordable. 

Most people with type 1 diabetes who use BGM alone need to check their blood glucose level at least four times every day.

 If you use an insulin pump, give yourself three or more insulin injections per day, or are currently pregnant, you may need to test as many as 10 times a day or more. 

If you use BGM alone, you may want to purchase several blood glucose meters to keep at home, work, school, and/or in a purse or backpack. This way you will be able to access your testing equipment wherever you are, making it easier to manage your blood glucose.

Type 2 diabetes — For people with type 2 diabetes, the recommendations for how often to test glucose levels are based upon individual factors such as type of treatment (oral medications, insulin, non-insulin injectable medications, and/or lifestyle changes), A1C level, risk of hypoglycemia (low blood glucose), and treatment goals.

Your healthcare provider will give you suggestions for the best times to check your blood sugar. This will vary from person to person.

It's especially important to check your blood sugar when you experience symptoms of low or high blood sugar.

There are also some general guidelines about which times of the day are most beneficial to check your blood sugar to assess how well your management plan is working.
 

Low blood sugar
Most people with diabetes have symptoms of low blood sugar (hypoglycemia) when their blood sugar is less than 70 mg/dL (milligrams per deciliter). When your blood sugar is low, your body gives out signs that you need food.
 

Common early symptoms of low blood sugar include:

• Weakness.
• Dizziness.
• Intense hunger (polyphagia).
• Trembling and feeling shaky.
• Sweating.
• Pounding heart.
• Feeling frightened or anxious.

When you have these symptoms, it’s important to check your blood sugar to see if your levels are low and how low they are. This will inform how you treat the low blood sugar.

You need to consume carbohydrates (sugar), like a banana or apple juice, to treat hypoglycemia. Severe hypoglycemia can be life-threatening.

High blood sugar
For people with diabetes, healthcare providers usually consider blood sugar levels above 180 mg/dL to be high blood sugar (hyperglycemia). However, most people with diabetes don’t feel symptoms of high blood sugar until their level is 250 mg/dL or higher.

High blood sugar can be dangerous to your health in the short term and long term, so it’s important to check your blood sugar if you’re experiencing the following symptoms:

• Increased thirst (polydipsia) and/or hunger.
• Frequent urination (peeing).
• Headache.
• Irritability.
• Blurred vision.

If you take insulin, you’ll need to treat the high blood sugar with insulin according to your healthcare provider’s instructions. If you have symptoms of diabetes-related ketoacidosis (DKA), such as those of high blood sugar with vomiting and fatigue, call your provider immediately. DKA is a life-threatening complication and needs immediate treatment.

Blood sugar monitoring during the day
Certain times of the day are most helpful to check your blood sugar to assess your overall diabetes treatment plan, especially if you take insulin. These times include:

• When you wake up: Your blood sugar level at this time is known as fasting glucose. It can help assess how your blood sugar levels are overnight, especially if you also check your blood sugar before you go to bed.
• Before meals: Checking your blood sugar before meals can help you plan your meal. If you take insulin, checking before a meal helps you to know how to dose for it. Checking before and after meals also helps you and your provider assess how food affects your blood sugar.
• After meals: Checking your blood sugar two hours after you start your meal can help you and your provider assess how food affects your blood sugar and if you need to change your insulin or medication doses. It’s common to experience high blood sugar after eating, especially if you need to take insulin.
• Before and after exercise: Checking your blood sugar before and after exercise can help you and your provider assess how that type of activity affects your blood sugar. Exercise typically lowers your blood sugar but it could also increase it, so checking afterward can help catch these episodes.
• Before you go to sleep: Checking your blood sugar before you go to sleep can catch potential low or high blood sugars. If you experience low blood sugar while you're sleeping, it can be more dangerous because you might not wake up right away from the symptoms. Consistently going to sleep with high blood sugar can be harmful to your health over the long term, because it'll likely be elevated for several hours while you're sleeping.

A blood glucose meter or glucometer is a device that measures the level of glucose in the blood. It is used by patients with diabetes to monitor their blood glucose levels and if necessary to help them regulate their insulin intake. They are generally used with test strips to collect droplets of blood. Nevertheless, alternatives that are less invasive and restrictive have emerged in recent years.

Given the prevalence of diabetes worldwide, the evolution of blood glucose monitoring systems is now a major global health concern. There are also models designed specifically for the veterinary field.

How do blood glucose meters work?
We can divide them into three different types: invasive, non-invasive and continuous.

• Invasive

  The measurement is made using a blood sample taken using a lancing device, lancets and test strips. These elements are often sold in kit form at the time of the first purchase. New strips and lancets then have to be replaced in pharmacies. Although constraining for the user, this type of blood glucose meter is the most accurate method of measurement.

• Non-invasive (or minimally invasive)

  In recent years, the market has seen the arrival of various measurement systems in the form of physico-chemical sensors in contact with the measurement area, usually the arm.
  Using the meter to scan the area gives you the blood glucose level almost instantly. This represents a real revolution for people with diabetes who no longer have to inject themselves half a dozen times a day or replace test strips and lancets. Nevertheless, there are limited options available on the market and the results so far have shown that the systems offered struggle to be as accurate as the invasive ones. Another disadvantage is the problem of sensors not staying in place.

• Continuous Glucose Monitoring (CGM)

  In this case, the blood glucose meter offers the possibility of continuous measurement. The patient wears the device, usually on his or her arm, and takes it everywhere. This type of model generally has an implantable sensor with a remote transmission system. It measures blood glucose levels in the interstitial fluid. It also makes it possible to more accurately assess changes in blood glucose levels over a long period of time. The continuous system reduces stress for patients who no longer have to prick their fingertips every day. The continuous system has its own constraints, however, such as maintenance and learning to use the device. Difficulties understanding and interpreting the data, sensor malfunctions and the difference in measurement between capillary blood glucose and the value displayed by continuous glucose measurement can be frustrating and may cause a user to decide not to use this type of device.

Glucose meters and test strips
The most common type of blood sugar monitoring involves using a glucose meter and test strips. This is a “finger stick check.” You prick your fingertip with a small needle called a lancet to produce a blood drop. You then place the drop against the test strip in the glucose meter, and the meter shows your blood sugar level within seconds.

Finger stick checks only measure blood glucose at one moment in time, so people often have to check their blood sugar several times a day using this method.

CGMs
CGM involves wearing a device that measures your glucose levels 24 hours a day. The device uses this data to form a graph that shows a more complete picture of how your blood sugar levels change over time.

Most CGM devices use a tiny sensor that you insert under your skin. The sensor measures glucose levels in the fluids between your body’s cells (interstitial fluid).
There are a few different types and brands of CGMs. Some CGMs link to specific insulin pumps. Others operate independently. Most CGMs can send alarms or alert messages when they detect low or high glucose levels.

Like all technology, CGMs can sometimes fail or be inaccurate. So, don’t completely rely on CGMs without finger stick checks, especially if your CGM readings don’t match the symptoms of low or high blood sugar you’re experiencing, or if your CGM gives you an error message.

Tracking blood sugar levels
Most glucose meters allow you to save the results. You may be able to use an app on your smartphone to track your levels. If you don’t have a smartphone, keep a written record of your blood sugar levels that includes the date, time of the test and any other details, like if it was before or after a meal. You should bring your glucose meter, phone or written record with you each time you visit your healthcare provider.

There are many different types of meters available for purchase that differ in several ways, including:

• accuracy
• amount of blood needed for each test
• how easy it is to use
• pain associated with using the
• product
• testing speed
• overall size
• ability to store test results in memory
• likelihood of interferences
• ability to transmit data to a computer
• cost of the meter
• cost of the test strips used
• doctor's recommendation
• technical support provided by the manufacturer
• special features such as automatic timing, error codes, large display screen, or spoken instructions or results

Talk to your health care provider about the right glucose meter for you, and how to use it.

A blood glucose meter must be adapted to each patient’s needs. Before buying a blood glucose meter, it is therefore necessary to take into account several factors such as ease of use and transport, the blood glucose measurement units displayed and the use of a chip (code).
Ease of use: the blood glucose meter interface must be intuitive and easily display the results and their description. Some models have a touch screen which is comfortable and easy to use. The device should preferably be of a size and shape that allows for a good grip.
Ease of transport: Since the patient must be able to measure their blood glucose level anywhere and at any time of the day, the ease of transport of the device is a very important factor to take into account. The patient will therefore be more inclined to choose a light space-saving model. Weight should not be a constraint, especially for young patients.
Blood glucose measurement units: Depending on the meter model, results may be given in g/l, mg/dl or in mmol/l. This can mislead a diabetic patient if he or she does not pay attention to the selected measurement unit (in the case of meters with multiple unit choices). The conversion of mg/dl to g/l is obtained by dividing the figure by 100. For example, if the meter is set in mg/dl and displays a result of 123, this means that the patient has a capillary blood glucose level of 1.23 g/l. The conversion from mmol/l to g/l is obtained by multiplying the mmol/l by 0.18.
Using a chip (or code): for some blood glucose meters, each box of test strips contains a specific chip that must be used and discarded after the box is finished. An incorrect adaptation of the meter/strip can lead to incorrect results. For meters that require this adaptation, it is essential to ensure before each measurement that the code displayed corresponds to the code on the test strip tube you are using. If this is not the case, no measurement should be made. There are also models that do not require a code to be entered to ensure the quality of the results.

Several measurement technologies are currently on the market. They are mainly electrochemical (enzymatic) and fall into three categories:

• By glucose oxidase
• By glucose dehydrogenase
• By glucose dye oxidoreductase

The results obtained may vary depending on the technology used. It is therefore always very important to use test strips that are compatible with the technology indicated on the meter.

One of the most common concerns people with diabetes have is how to know if their glucose meter is accurate.
Analyzing your device’s results against a controlled reading is the only way to evaluate the accuracy of your glucose meter. This can be done in two ways:
Lab Tests: The most common route is to check your blood glucose levels with your glucose meter at the same time as your blood is drawn for lab glucose tests and compare your meter’s measurement with the lab results. This is the most reliable way to make sure your glucose meter’s readings fit within the 15% variability window. Be sure your meter is calibrated to read whole glucose, which is what the lab result shows.
Control Solutions: Using a liquid control solution that has a known glucose level instead of a blood sample is another accepted way to check your glucometer’s accuracy. There is a wide array of control solutions, and most meters come with their own. You can use a control solution when you open a new test strip container, get odd glucose results, or fear you’ve damaged your glucose meter.

If for any reason your meter isn’t giving accurate measurements after testing, it’s best to either contact the manufacturer to troubleshoot the device or try a new glucose meter.

Choosing a More Accurate Glucose Meter
Accurate blood glucose measurement is a vital tool to manage diabetes and provide critical guidance for your doctor. This means it’s crucial to understand the factors that can affect your blood glucose levels and your blood glucose meter. Although testing your blood glucose meter’s accuracy is the only way to confirm it’s up to par, choosing a glucose meter from a reputable provider can help you achieve more accurate readings. An efficient and reliable blood glucose monitor is the best way to ensure you get the results you need to assess how well your diabetes is being controlled and make adjustments that can benefit you.

Blood glucose meter accuracy does not mean that it will show your exact blood glucose measurement or give the same reading if you test multiple times. Instead, meter accuracy is determined by how well it corresponds with lab results that are drawn in tandem with your blood glucose meter measurement. According to the FDA, accurate glucose meters provide results that are within ±15% of the lab 95% of the time. This means if your lab test results show a blood glucose value of 170, your glucose meter reading must fall between 145 and 195 to be considered within the window of accuracy.

What Can Affect Glucose Meter Accuracy?
A number of factors can affect the accuracy of your glucose meter.

Test Strips
To test your glucose levels, your blood sample is placed on a test strip and converted into a glucose measurement. This process can be affected by variables such as the following:

• Damage from being bent or torn
• Exposure to excess heat or moisture
• Contaminants on the strip or test site
• Incompatibility with the glucose meter
• Being past the expiration date

Suggestion: If you’re using a meter with separate test strips, you should always follow the manufacturer’s instructions to store your test strips at an appropriate temperature in a sealed container. This helps avoid damage from heat or humidity. Always wash your hands before applying blood to the test strip to avoid contamination.

Testing Site
Measurements from blood samples from sites other than your fingertip may be different due to the frequency with which your blood circulates through those areas. Capillary blood taken from the fingertip will have a more current blood glucose measurement than blood taken from the arm, for example, because it can take several minutes for blood to circulate to the forearm capillaries. As a result, when testing on alternate sites it is more difficult for your meter to detect immediate effects due to recent exercise, meals, or medication, which means your blood glucose reading may be higher or lower at that moment than it would be if measured using blood from a fingertip.
 

Suggestion: Talk with your doctor and read your glucose meter instructions to decide which testing site is right for you and how to best assess your results.

Inaccurate Coding
Certain meters require you to input a code for each container of test strips so the meter can be calibrated properly before use. If the code is incorrect, your meter may produce inaccurate readings.

Suggestion: It’s important to always make sure the code on your container matches the number you input into your meter so you won’t get inaccurate glucose measurements. You may also want to consider meters that don’t require a code for calibration to avoid this entirely.

Inadequate or Excessive Blood Samples
Placing too little or too much blood on the sample area of the test strip can cause measurement errors.

Suggestion: Always read the instructions that come with your meter to identify the necessary blood sample size needed for testing. It’s also best to avoid adding more blood to a test strip after you’ve applied the initial drop.

Red Blood Cell Volume
The number of red blood cells in your blood can influence how accurate your measurements are. Because of this, medical conditions like anemia can adversely affect your glucose meter results.

Suggestion: It’s best to speak with your doctor to know if you have any medical issues that can affect your red blood cell count. If you do, it may be best to confirm that your blood glucose meter’s specifications allow testing of someone with your red blood cell count. It’s also important to avoid dehydration, which can temporarily affect red blood cell count.

How to check your blood glucose — The following steps include general guidelines for testing blood glucose levels. However, because the instructions can vary between devices, it's best to check the package insert for your glucose meter or talk with your health care provider. It's important to never share monitoring equipment or fingerstick devices, as this could lead to infection. 

• Wash hands with soap and warm water, then dry.
• Prepare the lancing device by inserting a fresh lancet. Lancets that are used more than once are not as sharp as a new lancet and can cause more pain and injury to the skin.
• Prepare the blood glucose meter and test strip (the exact instructions for this depend upon the type of glucose meter used).
• Use the lancing device to obtain a small drop of blood from your fingertip or alternate site (like the skin of the forearm) . Alternate sites are often less painful than the fingertip. However, results from alternate sites are not as accurate as fingertip samples. This should not be a problem if you always use the same site. However, when your blood glucose is rising rapidly (eg, immediately after eating) or falling rapidly (in response to insulin or exercise), it's more accurate to use the fingertip, as testing at alternate sites may give significantly different results in these situations.
• If you have difficulty getting a good drop of blood from your fingertip, try rinsing your fingers with warm water and shaking your hand below your waist. This can help get the blood flowing.
• Apply the blood drop to the test strip in the blood glucose meter. The results will be displayed on the meter after several seconds.
• Dispose of the used lancet in a container designed for sharps (not in household trash).

Blood glucose meters — There is no single blood glucose meter that is better than others. Your health care provider or pharmacist can help you choose a meter based on your preferences as well as other factors like cost, ease of use, and accuracy; it should be one that is approved by either the International Organization for Standardization or the US Food and Drug Administration (FDA). Many insurance providers cover the cost of specific meters and/or supplies. 

Accuracy of home BGM — Blood glucose meters are reasonably accurate. However, there can be some variability between meters, so it is always wise to use caution and common sense. If you get a result that does not fit with how you feel (for example, if it says your blood glucose is very low but you don't have any symptoms), take a second reading or use an alternate method for testing your blood glucose (such as a different meter). Blood glucose meters are least accurate during episodes of low blood glucose. 

The accuracy of BGM can be affected by several factors, including the type of blood glucose strip and meter. Inaccurate readings can be caused by the use of expired strips, improper storage of strips (exposure to high temperature and humidity), inadequate cleansing of your skin, and ingestion of vitamin C and acetaminophen.

It's a good idea to check the accuracy of your blood glucose meter occasionally by bringing it with you when you have an appointment to get blood testing. This way, you use your home monitor to check your blood glucose at the same time that blood is drawn and compare the results. If the results differ by more than 15 percent, there may be a problem with your meter or other equipment; your provider can help you figure out what's going on and how to correct the problem.

There are different kinds of meters, but most of them work the same way. Below are tips for how to use a blood sugar meter.

1. Make sure the meter is clean and ready to use.
2. After removing a test strip, immediately close the test strip container tightly. Test strips can be damaged if they are exposed to moisture.
3. Wash your hands with soap and warm water. Dry well. Massage your hand to get blood into your finger. Don’t use alcohol because it dries the skin too much.
4. Use a lancet to prick your finger. Squeezing from the base of the finger, gently place a small amount of blood onto the test strip. Place the strip in the meter.
5. After a few seconds, the reading will appear. Track and record your results. Add notes about anything that might have made the reading out of your target range, such as food, activity, etc.
6. Properly dispose the lancet and strip in a trash container.
7. Do not share blood sugar monitoring equipment, such as lancets, with anyone, even other family members.
8. Store test strips in the container provided. Do not expose them to moisture, extreme heat, or cold temperatures.

Test strips are part of many tests for home use that allow people to test for or monitor some diseases or health conditions, including diabetes. The FDA is aware that some sellers are marketing pre-owned or secondhand test strips to consumers. These are unused test strips previously owned by someone else.

These pre-owned strips may be sold at lower prices when compared to new strips. For instance, you may see flyers advertising cheap test strips in your neighborhood, or you may see sellers marketing cheap test strips online. But pre-owned strips can give incorrect results and may not be safe for use with devices.

For more detailed information about the risks associated with pre-owned test strips, please see, “The FDA Warns Against Use of Previously Owned Test Strips or Test Strips Not Authorized for Sale in the United States.”

Here’s more information to consider.
 

• Test strips should be properly stored to give accurate results. If you buy pre-owned strips, it is hard to know whether the strips were stored properly. Test strips also could be expired. A lack of proper storage or using expired strips could put you at risk for getting incorrect results from your glucose meter. And incorrect results can put you at risk for serious health complications — and even death.
• Test strip vials that have been opened by another person may have small amounts of blood on them, which can put you at risk for infection.
• Pre-owned test strip vials may have been tampered with, which means that they may not be safe to use. For instance, the expiration dates might have been changed or covered up.
• Pre-owned strips also may not have been cleared by the FDA for sale in the United States. If instructions aren’t in English or the strips look different than other strips of the same brand, this can be a sign of unsafe strips.
  The bottom line? When it comes to buying test strips—including glucose test strips designed for your meter—the FDA recommends that you buy new, unopened vials and that you do not buy pre-owned test strips.
  Talk to your health care provider if you are not sure where to buy test strips for your glucose meter or if you cannot afford to buy the test strips recommended for use with your meter.

It is important for users to understand that if they use a test strip that is not recommended for their meter, the device may fail to give results or may generate inaccurate results.

Recommendations: Users of blood glucose meters should carefully read the Owner’s Manual and only use the test strips that are specified for that meter. As an additional check, the test strip inserts identify the blood glucose meters with which they should be used.

You may be a pro at testing your blood sugar levels. But consider these safety reminders:
Follow instructions carefully. Glucose meters and test strips are sold with instructions for use. You can call the manufacturer of your device or your health care provider if you have questions.

Ask your health care provider to watch you test yourself. He or she can tell you if you are using your device correctly.

Do quality control checks of your device. Regularly test your meter using a control solution to make sure the test strips and meter are working properly together. Read the meter’s instructions for use to see how often you should test it.

Understand what the meter display means. Be sure you know how high and low glucose values are displayed on your meter. Sometimes they are displayed as “LO” or “HI” when the glucose level is beyond the range than the meter can measure. Talk to your health care provider if you have questions.

Know which test site gives the most accurate results. Readings from other areas of your body may not be as correct as fingertip readings.

• Readings from alternate sites—such as your forearm or palm—can be less accurate than fingertip readings when your glucose levels change quickly, for example, after you eat or during exercise.
• Take a reading from a fingertip if you think your blood glucose is low, if you don't normally have symptoms when your blood glucose is low, or if results from an alternate test site don’t match how you feel.

Know when and how to clean and disinfect your glucose meter. Cleaning and disinfection instructions can vary, so always read and follow the directions in your manual.

Know when to report device problems. In an emergency, call 9-1-1. For non-emergencies, the FDA encourages you to report any issues to MedWatch, the FDA’s voluntary reporting program. (Problems may include devices that don’t work, suspected incorrect results, or any other problem with your meter or test strips.)

The following standard recommendations are from the American Diabetes Association (ADA) for people who have diagnosed diabetes and are not pregnant. Work with your doctor to identify your personal blood sugar goals based on your age, health, diabetes treatment, and whether you have type 1 or type 2 diabetes.

Your range may be different if you have other health conditions or if your blood sugar is often low or high. Always follow your doctor’s recommendations.
Below is a sample record to discuss with your doctor.

Glucose testing — The results of glucose testing with blood glucose monitoring (BGM) or continuous glucose monitoring (CGM) tell you how well your diabetes treatments are working. Glucose results can be affected by different things, including your level of physical activity, what you eat, stress, and medications (including insulin, non-insulin injectable medications, and oral diabetes medications). To fully understand what your glucose levels mean, it is important to consider all of these factors.

When keeping track of your results, you should include the time and date, glucose result, and the medication and dose you are taking. Additional notes about what you ate, whether you exercised, and any difficulties with illness or stress can also be helpful but are not generally required every day. You should review this information regularly with your health care provider to understand what your results mean and whether you need to make any changes to better manage your glucose levels.

Need for urine testing — If you have type 1 diabetes, your health care provider will talk to you about checking your urine for ketones. You will need to do this if your glucose level gets above 250 to 300 mg/dL (13.9 to 16.7 mmol/L), during periods of illness or stress, or if you have symptoms of a problem called ketoacidosis (such as nausea, vomiting, and abdominal pain).

Ketones are acids that are formed when the body does not have enough insulin to get glucose into the cells, causing the body to break down fat for energy. Ketones can also develop during illness, if an inadequate amount of glucose is available (due to skipped meals or vomiting). Ketoacidosis is a condition that occurs when high levels of ketones are present in the body; it can lead to serious complications such as diabetic coma.

Urine ketone testing is done with a dipstick, available in pharmacies without a prescription. If you have moderate to large ketones, you should call your health care provider immediately to determine the best treatment. You may need to take an additional dose of insulin, or your provider may instruct you to go to the nearest emergency room. Meters that measure ketone levels in the blood are also available, but due to their cost, urine testing is more widely used.

Continuous glucose monitoring automatically tracks blood glucose levels, also called blood sugar, throughout the day and night. You can see your glucose level anytime at a glance. You can also review how your glucose changes over a few hours or days to see trends. Seeing glucose levels in real time can help you make more informed decisions throughout the day about how to balance your food, physical activity, and medicines.

A CGM works through a tiny sensor inserted under your skin, usually on your belly or arm. The sensor measures your interstitial glucose level, which is the glucose found in the fluid between the cells. The sensor tests glucose every few minutes. A transmitter wirelessly sends the information to a monitor.

The monitor may be part of an insulin pump or a separate device, which you might carry in a pocket or purse. Some CGMs send information directly to a smartphone or tablet. Several models are available and are listed in the American Diabetes Association’s product guide External link.

Most people who use CGMs have type 1 diabetes. Research is underway to learn how CGMs might help people with type 2 diabetes.
CGMs are approved for use by adults and children with a doctor’s prescription. Some models may be used for children as young as age 2. Your doctor may recommend a CGM if you or your child:

• are on intensive insulin therapy, also called tight blood sugar control
• have hypoglycemia unawareness
• often have high or low blood glucose

Your doctor may suggest using a CGM system all the time or only for a few days to help adjust your diabetes care plan.

Compared with a standard blood glucose meter, using a CGM system can help you
 

• better manage your glucose levels every day
• have fewer low blood glucose emergencies
• need fewer finger sticks

A graphic on the CGM screen shows whether your glucose is rising or dropping—and how quickly—so you can choose the best way to reach your target glucose level.

Over time, good management of glucose greatly helps people with diabetes stay healthy and prevent complications of the disease. People who gain the largest benefit from a CGM are those who use it every day or nearly every day.