Managing diabetes | Abbott

When it comes to diabetes, knowledge is power. Explore the topics below to stay informed and help better manage your diabetes.

What is A1C?

A1C is a measurement of your average glucose levels over the past three months.^1,2 It’s used by healthcare professionals to measure how well your diabetes is being managed and is given as a percentage.¹

The goal for most people with type 1 or type 2 diabetes is an A1C below 7%.³

What’s a normal blood sugar level?

Recommended blood sugar levels for most people with diabetes⁴

This table provides general recommendations on blood sugar targets and may not be the same as the targets your healthcare team has set for you. Your targets should be personalized to you.

	Target
A1C	7.0% or under
Fasting blood glucose (sugar)/blood glucose before meals	4.0-7.0 mmol/L
Blood glucose (sugar) two hours after eating (mmol/L)	5.0-10.0 mmol/L (5.0-8.0 mmol/L if A1C targets are not being met)

Doctors also use different blood sugar tests to diagnose diabetes. In addition to A1C, doctors will do a Fasting Blood Sugar Test (measures blood sugar levels after an overnight fast) and a Glucose Tolerance Test (measures blood sugar levels before and after drinking a sugary liquid).⁵

Diabetes is diagnosed when:⁵

A1C is 6.5% or above
Blood sugar level is 7 mmol/L or higher after fasting
Blood sugar level is 11.1 mmol/L or higher 2 hours after drinking a sugary liquid

Prediabetes is diagnosed when:⁵

A1C is 5.7-6.4%
Blood sugar level is 5.6-6.9 mmol/L after fasting
Blood sugar level is 7.8-11.0 mmol/L 2 hours after drinking a sugary liquid

	A1C Test	Fasting Blood Sugar Test	Glucose Tolerance Test
Diabetes	6.5% or higher	7 mmol/L or higher	11.1 mmol/L or higher
Prediabetes	5.7-6.4%	5.6-6.9 mmol/L	7.8-11.0 mmol/L
Normal	Under 5.7%	Under 5.6 mmol/L	Under 7.8 mmol/L

How A1C is measured

When glucose is in your bloodstream, it enters your red blood cells and attaches to a protein called “hemoglobin”. A1C is a measurement of the percentage of hemoglobin in your blood that’s attached to glucose.^1,6

A1C and glucose variability

Whatever your A1C, it’s possible to spend a significant amount of time outside of your target glucose range (which is where you and your diabetes care team would like your glucose levels to be).^7-9 This is why Time in Range should be considered in addition to your A1C.

Consider the following example. These three people all have an A1C of 7%. Person A has spent 100% of the time in their target glucose range while persons B and C have not. Persons B and C have a good A1C, but they’re experiencing glucose variability.

Patient A

Patient B

Patient C

Above Target Range (hyperglycemia)

In Target Range

Below Target Range (hypoglycemia)

For illustrative purposes only. Not actual patient data.

The Triangle of Diabetes Care

The Triangle of Diabetes Care is an approach to managing your diabetes that goes beyond simply lowering your A1C. Although A1C is an important indicator of your glucose control, research suggests that we should also look at other factors for a better picture of glycemic control.¹⁰

By targeting each of the three goals of the Triangle of Diabetes Care, you can help make improvements to your wellbeing as well as your long-term health.¹¹ The main three goals are:

Improve your A1C, in line with your personal goals
Reduce or limit the swings between low and high glucose levels (also called “glucose variability”)
Reduce the frequency of hypoglycemia (low glucose)

Achieving all three of these goals leads to better diabetes management.

The Triangle of Diabetes Care was developed by Dr. Ramzi Ajjan, Associate Professor and
Consultant in Diabetes and Endocrinology at the University of Leeds.

Tips for using your FreeStyle Libre or FreeStyle Libre 2 system to help achieve these three goals

1. Better manage overall glucose levels (A1C)

Frequent glucose testing helps you to keep an accurate record of your glucose levels and achieve better long-term glycemic control.¹² In fact, real-life use has shown that people who scan frequently to check their glucose levels lowered their A1C.¹³

2. Limit glucose variability

The FreeStyle Libre and FreeStyle Libre 2 systems allow you to see upward or downward trends using the Trend Arrows, and the Daily Patterns report can show you where you have the most variability in your glucose readings from day to day. If you start to see that your glucose runs low or high at specific times of the day, or in response to particular activities, these can be identified so you can make changes in the future.

3. Minimize hypoglycemia

The Low Glucose Events report on your FreeStyle LibreLink app* or FreeStyle Libre 2 app^† lets you see when and how often your glucose is low throughout a typical day, so you can try and reduce the risk of another hypo (hypoglycemia).

Understanding Time in Range

What is it, and what does it mean?

Time in Range refers to the amount of time each day that you spend within your target glucose range.

When setting up your FreeStyle Libre or FreeStyle Libre 2 system for the first time, you need to enter the upper and lower values for the Target Glucose Range in the Settings in the FreeStyle LibreLink app* or the FreeStyle Libre 2 app,^† with your healthcare professional’s guidance.

Time in Range is another way of talking about Time in Target, which is one of the reports available on the FreeStyle LibreLink app* and the FreeStyle Libre 2 app.^† The more time you spend in your target range, the better.

Time Below Range and Time Above Range are also important measures. The Time in Target report on the FreeStyle LibreLink app* or FreeStyle Libre 2 app† will show you the percentage of time you’re spending below target range, above target range, and within target range.

In the example below, the Time in Target report shows that this person has spent 22% of the time above target range, 75% of the time within target range, and 3% of the time below target range.

This person has spent 75% of the time in target range

6% Glucose is high

16% Above target range

75% Within target range

3% Glucose is low

Product images are for illustrative purposes only. The examples provided are not intended to be a substitute for professional medical advice. Please consult your physician or qualified health provider regarding your condition and appropriate diabetes plan. Individual symptoms, situations and circumstances may vary.

Expert medical opinion indicates that a target glucose range of 3.9-10 mmol/L should be used to assess Time in Range for most adults with type 1 or type 2 diabetes who are not pregnant, older or considered high-risk.¹⁴ Consult with your healthcare team to set target range values that are right for you.

Increased Time in Range can mean fewer diabetes complications

Information from a major clinical trial in people with type 1 diabetes has shown that spending more Time in Range can help to avoid harmful diabetes complications. People in the trial who developed problems with their kidneys or their eyes spent 10-12% less Time in Range than those who did not.¹⁵

A different study on people with type 2 diabetes showed that vision-threatening eye problems were most common in people who spent the least amount of time in their target glucose range, regardless of A1C level.¹⁶

More Time in Range

Lower risk of eye and kidney problems

How much time do you need to spend “in range”?

An international group of diabetes experts has recommended that spending at least 70% of your time (~17 hours/day) in range is advisable for most adults with type 1 or type 2 diabetes who are not pregnant, older or considered high-risk.¹⁴

Of course, not everyone will be able to meet this target, or at least not right away. Making improvements in Time in Range will vary for each person with diabetes, and that’s okay. Keep in mind that even small increases in Time in Range can have a positive impact.¹⁴ So don’t get discouraged - keep scanning regularly and sticking with your diabetes management plan!

Recommended targets for Time in Range, Time Below Range and Time Above Range for most adults with type 1 and type 2 diabetes who are not pregnant, older or considered high-risk¹⁴

	Measure	Interpretation	Target
Time in Range	3.9-10 mmol/L	- No action needed	70% or more (16 h, 48 min per day)
Time Below Range – Level 1 hypoglycemia	<3.9 mmol/L	- Action needed if symptoms occur or if extended duration	Under 4% (1 h per day)
Time Below Range – Level 2 hypoglycemia	<3.0 mmol/L	- Immediate action needed	Under 1% (15 min per day)
Time Above Range – Level 1 hyperglycemia	>10 mmol/L	- Low priority for immediate action	Under 25% (6 h per day)
Time Above Range – Level 2 hyperglycemia	>13.9 mmol/L	- Immediate action needed to avoid unwanted effects of hyperglycemia (e.g., diabetic ketoacidosis)	Under 5% (1 h, 12 min per day)

A closer look at hypoglycemia

Why is hypoglycemia important?

Non-severe (mild or moderate), which can be self-treated
Severe, which requires help from another person for recovery

Recognizing hypoglycemia when it happens

Common symptoms of hypoglycemia include:¹⁹

Shaking

Pounding heart

Sweating

Hunger

Nausea

Headache

Confusion

Odd behaviour

Drowsiness

Difficulty with speech

Lack of coordination

Children tend to experience behavioural changes while older people may also experience neurological symptoms such as visual disturbance, mental impairment, lightheadedness, unsteadiness and poor concentration.^20,21

Keep in mind that symptoms can vary between events and can change over time.¹⁹

When do you start feeling symptoms of hypoglycemia?

In general, people will start to experience symptoms of hypoglycemia when their glucose levels are 2.8-3.2 mmol/L. When glucose levels are 2.8-3.0 mmol/L, this is when people may start to notice impaired mental function.

Levels below 1.5 mmol/L are very dangerous, and people can experience a reduced level of consciousness, convulsions and coma. Keep in mind that these are approximate thresholds and they can vary in people with diabetes.¹⁷

How does hypoglycemia affect our mood and emotions?

Hypoglycemia can make us feel more than just irritable. It can also make us angry and irrational, and in some cases (as with recurrent hypoglycemia) can even lead to anxiety.²²

Hypoglycemia can:²²

Provoke tense-tiredness (a feeling of being both tense and tired at the same time) and feelings of unhappiness

Increase irritability and anger

Make us pessimistic about everyday situations and about life issues

Lead to mood changes, which are negative, stressful and unpleasant

Lead to anxiety (with repeated episodes of hypoglycemia)

What does mental impairment look like?

Studies have shown that mental function starts to become affected when glucose levels fall below 3.0 mmol/L. Below this level, people with diabetes may start to experience problems with:¹⁷

Fine motor coordination
Mental speed
Concentration
Certain memory functions (e.g., word recall, working memory)

Uncommon but serious consequences of hypoglycemia

Brain

Coma, seizures, mental impairment, psychological effects¹⁷

Bones

Falls, accidents, dislocations, driving mishaps¹⁷

Heart

Angina (a type of chest pain), abnormal heart rhythms, heart failure^17,23

Causes and risk factors for hypoglycemia

Insufficient food or missed meals (most common cause)
Taking too much insulin or sulfonylurea medication
Alcohol consumption (especially if you haven’t eaten)
Physical exercise
Delayed emptying of the stomach

Increasing age
Duration of type 1 diabetes
Duration of treatment with insulin in people with type 2 diabetes
Previous episodes of severe hypoglycemia (most powerful predictor of future episodes)
Impaired awareness of hypoglycemia
Kidney disease
Decreased mental ability (e.g., depression)
Strict control of blood glucose
Increased glucose variability

How is hypoglycemia treated?

Non-severe hypoglycemia can be self-treated. If you have symptoms of hypoglycemia and your glucose level is less than 3.9 mmol/L, follow these steps:

Eat or drink 15-20 grams of a fast-acting carbohydrate, such as:
- 4 glucose tablets; or
- 1 tube of glucose gel; or
- ½ cup (4 ounces) of fruit juice (NOT low-calorie or reduced-sugar juice) – apple, grape and cranberry juices are good options; or
- ½ can (4-6 ounces) of pop (NOT diet or reduced sugar); or
- 1 tablespoon of sugar, honey or corn syrup
Check your glucose level again after 15 minutes. If your level is still low, eat or drink another 15-20 grams of a fast-acting carbohydrate, as mentioned above.
Continue to check your glucose levels every 15 minutes. Repeat the steps above until your glucose levels are back to normal.

Severe hypoglycemia has to be treated by other people. The best way to treat severe hypoglycemia is with glucagon - a hormone that raises your glucose levels. Glucagon is available as a nasal spray and injection, and can quickly bring your glucose levels back up. You or your caregiver should also seek immediate medical assistance, even if you’ve been given glucagon.²⁶

Helpful tips for managing hypoglycemia

Follow an eating plan, including carbohydrate counting
Monitor glucose before and after exercise
Eat a snack before exercise if glucose level is low or falling
Modify physical activity that’s caused hypoglycemia in the past
Take care with prolonged or unaccustomed exercise
Watch out for delayed hypoglycemia (several hours after exercise – often during the nighttime)

Test glucose before driving and during long journeys (every 2 hours)
Have a snack before driving if glucose is <5.0 mmol/L; do not drive if <4.0 mmol/L
Take regular meals/snacks and take a rest period during journeys
Keep an emergency supply of fast-acting carbohydrate in your car AND an additional supply of food
Stop the car in an appropriate location if hypoglycemia happens
Delay restarting driving until 45 minutes after glucose has returned to normal

Using Trend Arrows on your FreeStyle Libre or FreeStyle Libre 2 system to help you avoid hypoglycemia

The Trend Arrows on your glucose reading can be used to estimate the direction your glucose is heading. This is especially useful to know if your glucose is lowering and you might be heading towards a hypo (hypoglycemia).

If you see a downward angled Trend Arrow you know that your glucose is falling. Knowing this, along with your current reading, you can estimate if this is going to take you into the hypoglycemia zone (below 4.0 mmol/L) and take action to bring your glucose back to target as your healthcare team advised you.

Example: Your glucose reading is 4.4 mmol/L and you have a falling Trend Arrow.

Important note:
Keep in mind that the downward angled arrow indicates that your glucose is changing at a slower rate (0.06 mmol/L per minute), whereas the downward pointing arrow indicates that your glucose is changing at a faster rate (0.1 mmol/L per minute).

Let’s say that you want to estimate where your glucose level will be in 15 minutes. Just follow these steps:

Use the following calculation to estimate how much your glucose level will change over 15 minutes based on a slower and faster rate of change:
- Slower rate of change: 0.06 mmol/L/minute x 15 minutes = 0.9 mmol/L
- Faster rate of change: 0.1 mmol/L /minute x 15 minutes = 1.5 mmol/L
Next, you will SUBTRACT these values from your current glucose reading. This will give you an estimate of your glucose level 15 minutes from now.
- Slower rate of change: 4.5 mmol/L - 0.9 mmol/L = 3.6 mmol/L
- Faster rate of change: 4.5. mmol/L - 1.5 mmol/L = 3.0 mmol/L

So, in this example, your estimated glucose level in 15 minutes will be between 3.6 mmol/L and 3.0 mmol/L. In this instance, it’s really important to take action right away to stop yourself from having a hypo.

A quick table to help guide you:

	Calculating how much your glucose level will change after a certain amount of time	Calculating your estimated glucose level after a certain amount of time
Slower rate of change	0.06 x [number of minutes] = [change in glucose level (mmol/L)]	[current glucose level] + [change in glucose level] = [lower level of glucose]
Faster rate of change	0.1 x [number of minutes] = [change in glucose level (mmol/L)]	[current glucose level] + [change in glucose level] = [upper level of glucose]
Slower rate of change	0.06 x [number of minutes] = [change in glucose level (mmol/L)]	[current glucose level] - [change in glucose level] = [upper level of glucose]
Faster rate of change	0.1 x [number of minutes] = [change in glucose level (mmol/L)]	[current glucose level] - [change in glucose level] = [lower level of glucose]

IMPORTANT: There are many factors influencing your glucose levels, so although this is handy to know, it’s important to understand that this is only for guidance. Plus, if math just isn’t your thing and you really want to know your glucose reading at any point in time, you can always just re-scan.^‡

Take advantage of the Low Glucose Events report on your FreeStyle Libre/FreeStyle Libre 2 system

The “Low Glucose Events” report from the FreeStyle Libre and FreeStyle Libre 2 systems are a good way to see if any particular part of your day is contributing to episodes of hypoglycemia (hypos). It puts you in the know, so you can make changes to reduce or even avoid hypos.

The FreeStyle Libre and FreeStyle Libre 2 systems record a Low Glucose Event whenever your glucose has fallen below 3.9 mmol/L for more than 15 minutes. The bar graph displays the low glucose events that happened during different periods of the day - overnight, morning, afternoon or evening.

If you are using the FreeStyle Libre 2 system, remember that you can set a “low glucose alarm” on your app.^† This will alert you day and night when your glucose level passes the value you have set, even before you experience hypoglycemia.

Results that matter

Studies have shown that FreeStyle Libre users spend less time below 3.9 mmol/L than people who use finger prick blood glucose testing.^29,30 This important improvement is not just during the day, but also at night when many people may worry about having a hypo.

Be prepared for your next visit with your healthcare professional!

Learn how you can use reports from the FreeStyle Libre or FreeStyle Libre 2 system to have a more productive conversation with your doctor.

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* The FreeStyle LibreLink app and the FreeStyle Libre reader have similar but not identical features. A finger prick test using a blood glucose meter is required during times of rapidly changing glucose levels when interstitial fluid glucose levels may not accurately reflect blood glucose levels or if hypoglycemia or impending hypoglycemia is reported by the FreeStyle LibreLink app or when symptoms do not match the app readings. The FreeStyle Libre sensor communicates with the FreeStyle Libre reader that started it or the FreeStyle LibreLink app that started it. A sensor started by the FreeStyle Libre reader will also communicate with the FreeStyle LibreLink app. The FreeStyle LibreLink app is only compatible with certain mobile devices and operating systems. Please check the Compatibility Guide (PDF 69 kB) for more information about device compatibility before using the app. Use of FreeStyle LibreLink requires registration with LibreView.

† The FreeStyle Libre 2 app and the FreeStyle Libre 2 reader have similar but not identical features. Finger pricks are required if glucose readings and alarms do not match symptoms or expectations. The FreeStyle Libre 2 sensor communicates with the FreeStyle Libre 2 reader that started it or the FreeStyle Libre 2 app that started it. The FreeStyle Libre 2 app is only compatible with certain mobile devices and operating systems. Please check the Compatibility Guide (PDF 69 kB) for more information about device compatibility before using the app. Use of FreeStyle Libre 2 requires registration with LibreView.

‡ Finger pricks are required if glucose readings and alarms do not match symptoms or expectations. 

References:

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Ajjan RA and Owen KR. Glucokinase MODY and implications for treatment goals of common forms of diabetes. Curr Diab Rep 2014;14:559-65.
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McCrimmon RJ, et al. Symptoms of hypoglycemia in children with IDDM. Diabetes Care 1995;18(6):858-61.
Jaap AJ, et al. Perceived symptoms of hypoglycemia in elderly type 2 diabetic patients treated with insulin. Diabet Med 1998;15:398-401.
Gold AE, et al. Hypoglycemia and non-cognitive aspects of psychological function in insulin-dependent (type 1) diabetes mellitus (IDDM). Diabet Med 1997;14:111-18.
Rana O, et al. Acute hypoglycemia decreases myocardial blood flow reserve in patients with type 1 diabetes mellitus and in healthy humans. Circulation 2011;124(14):1548-56.
Kedia N. Treatment of severe diabetic hypoglycemia with glucagon: an underutilized therapeutic approach. Diabetes Metab Syndr Obes 2011;4:337-46.
Frier BM. Hypoglycaemia in diabetes mellitus: epidemiology and clinical implications. Nat Rev Endocrinol 2014;10(12):711-22.
Low blood glucose (hypoglycemia). National Institute of Diabetes and Digestive and Kidney Diseases. Updated July 2021. Available at: https://www.niddk.nih.gov/health-information/diabetes/overview/preventing-problems/low-blood-glucose-hypoglycemia#likely. Accessed September 14, 2022.
Seaquist ER, et al. Hypoglycemia and diabetes: a report of a workgroup of the American Diabetes Association and the Endocrine Society. Diabetes Care 2013;36:1384-95.
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Bolinder J, et al. Novel glucose-sensing technology and hypoglycemia in type 1 diabetes: a multicentre, non-masked, randomized controlled trial. Lancet 2016;388:2254-63.
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The FreeStyle Libre 2 flash glucose monitoring system is indicated for measuring interstitial fluid glucose levels in people aged 4 years and older with diabetes mellitus. Always read and follow the label/insert.