Keeping blood sugar levels in check often requires frequent at-home tests.
Doctors use blood sugar charts to set target goals and monitor diabetes treatment plans. Blood sugar charts also help those with diabetes assess and self-monitor blood sugar test results.
Contents of this article:
What is a blood sugar chart?
Blood sugar charts act as a reference guide for blood sugar test results. As such, blood sugar charts are important tools for diabetes management.
Most diabetes treatment plans involve keeping blood sugar levels as close to normal or target goals as possible. This requires frequent at-home and doctor-ordered testing, along with an understanding of how results compare to target levels.
To help interpret and assess blood sugar results, the charts outline normal and abnormal blood sugar levels for those with and without diabetes.
In the United States, blood sugar charts typically report sugar levels in milligrams per deciliter (mg/dL). In the United Kingdom and many other countries, blood sugar is reported in millimoles per liter (mmol/L).
A1C blood sugar recommendations are frequently included in blood sugar charts. A1C results are often described as both a percentage and an average blood sugar level in mg/dL.
An A1C test measures the average sugar levels over a 3-month period, which gives a wider insight into a person's overall management of their blood sugar levels.
Blood sugar chart guidelines
Appropriate blood sugar levels vary throughout the day and from person to person.
Blood sugars are often lowest before breakfast and in the lead up to meals. Blood sugars are often highest in the hours following meals.
People with diabetes will often have higher blood sugar targets or acceptable ranges than those without the condition.
These targets vary according to a range of factors that include:
- age and life expectancy
- other health conditions
- how long someone has had diabetes for
- known cardiovascular disease
- problems with the smallest arteries in the body
- any known damage to the eyes, kidneys, blood vessels, brain, or heart
- personal habits and lifestyle factors
- low blood sugar level unawareness
Most blood sugar charts show recommended levels as a range, allowing for differences between individuals.
The American Diabetes Association (ADA), Joslin Diabetes Center (JDC), and American Association of Clinical Endocrinologists (AACE) also offer slightly different blood sugar guidelines for those with diabetes.
|Time of check||Blood sugar levels for those without diabetes||Target blood sugar levels for those with diabetes|
|Fasting (before breakfast)||less than 100 mg/dL||80 - 130 mg/dL (ADA)
70-130 mg/dL (JDC)
less than 110 (AACE)
|Before meals||less than 110 mg/dL||70-130 mg/dL (JDC)|
|2 hrs after meal
1-2 hrs after meal
|less than 140 mg/dL||less than 180 mg/dL (ADA & JDC)
less than 140 (AACE)
|Bedtime||less than 120 mg/dL||between 90 - 150 mg/dL (JDC)|
|A1C levels||less than 5.7 percent||less than 7 percent|
Interpreting blood sugar meter results
Interpreting blood sugar meter readings depends a lot on individual norms and targets.
A good blood sugar level for one person may be too high or low for someone else. However, for people with diabetes, some ranges of blood sugar levels are preferable over others.
|Blood sugar level||Excellent||Good||Acceptable|
|Before meal||72 - 109 mg/dL||110 - 144 mg/dL||145 - 180 mg/dL|
|2 hours after meal||90 - 126 mg/dL||127 - 180 mg/dL||181 - 234 mg/dL|
Certain forms of temporary diabetes, such as gestational diabetes, also have separate blood sugar recommendations.
|Time of check||Blood sugar level in mg/dL|
|Fasting or before breakfast||60 - 90 mg/dL|
|Before meals||60 - 90 mg/dL|
|1 hour after meal||100 - 120 mg/dL|
Anyone who has very high or low fasting blood sugar levels should be concerned.
|Fasting blood sugar level||Risk level and suggested action|
|50 mg/dL or less||Dangerously low, seek medical attention|
|70 - 90 mg/dL||Possibly too low, get sugar if experiencing symptoms of low blood sugar or see a doctor|
|90-120 mg/dL||Normal range|
|120-160 mg/dL||Medium, see a doctor|
|160 - 240 mg/dL||Too high, work to lower blood sugar levels|
|240-300 mg/dL||Too high, a sign of out of control diabetes, see a doctor|
|300 mg/dL or above||Very high, seek immediate medical attention|
As long as levels aren't critically dangerous, there are ways to reduce blood sugar levels when readings are too high.
Ways to lower blood sugar include:
- limiting carbohydrate intake but not fasting
- increasing water intake to maintain hydration and dilute excess blood sugar
- increasing physical activity to burn excess blood sugar
- increasing fiber intake
These methods are not a replacement for prescribed treatment but rather an addition to any treatment plan. If blood sugar readings seem unusual or unexpected, consult a doctor. Various user and device factors can influence blood sugar readings, causing them to be inaccurate.
Monitoring blood sugar levels
Monitoring blood sugar levels is an important part of diabetes management. The best monitoring plans often rely on both self-monitoring at home and doctor-ordered tests, such as A1C tests.
Many types of blood sugar monitors are available for self-monitoring. Most blood sugar monitors in the U.S. involve using blood obtained from a finger prick and testing strips. These give blood sugar readings in mg/dL.
Recently, home blood sugar meters have been made to produce plasma glucose counts instead of whole blood glucose counts. This change allows more accurate readings of daily blood glucose levels. It is also easier to directly compare the results of self-monitoring and doctor-ordered tests as doctors also use plasma glucose counts.
The amount of tests done per day will vary depending on the type of diabetes and the individual's treatment plan.
Tracking daily blood sugar level changes can help doctors understand how treatment plans are working and adjust medications or targets. It can also help reflect the impact of diet and exercise.
The frequency of blood sugar tests varies between individual treatment plans, as well as the type or stage of diabetes:
- Type 1 - adult: At least twice daily, up to 10 times. Tests should be done before breakfast, at fasting, before meals, sometimes 2 hours after meals, before and after physical activities, and at bedtime.
- Type 1 - child: At least four times daily. Tests should be done before meals and at bedtime. Tests may also be required 1-2 hrs after meals, before and after exercise, and overnight.
- Type 2 - on insulin or other management medications: Recommended testing frequency varies depending on insulin dosage and use of additional medications. Those on intensive insulin should do tests at fasting, before meals, before bedtime, and sometimes overnight. Those on insulin and additional medications should at least perform tests at fasting and bedtime. Those on basal insulin and one daily premixed insulin injection should perform tests when fasting, before premixed dosages and meals, and sometimes overnight. Those not on insulin but oral medications or diet control require much less frequent blood sugar testing at home.
- Type 2 - low risk of low blood sugar: Often daily tests are not required. Performing tests at mealtimes and bedtime should reflect the real-time impact of lifestyle changes. If blood sugar goals or A1C levels are not being met, the frequency of testing should increase until levels are back within normal ranges.
- Gestational: Those on insulin should perform tests at fasting, before meals and 1 hour after meals. Those not on insulin should perform tests at fasting and 1 hour after meals.
Blood sugar testing should be increased during periods of physical and emotional stress, such as pregnancy, acute illness, or depression.
Devices known as continuous glucose monitors (CMGs) are available for those who have difficulty managing blood sugar meters or blood sugars. CMGs consist of a sensor placed under the skin that measures the amount of sugar in tissue.
If blood sugar levels rise too high above or fall too far below preset targets, an alarm will go off. Some CMGs will also track how blood sugar levels change over the course of hours and display whether levels are raising or falling.
CMGs must be checked regularly with finger-prick meter results. For the best results, tests should be done during times when blood sugar levels are steady, away from events, such as meals and physical activity.