From the Guidelines

Creator: Dr.Oracle Medical Advisory Board
Published: 2025-02-18T14:28:13.718Z

The normal blood glucose ranges are:

Fasting blood glucose: 70-99 mg/dL
Postprandial (after meal) blood glucose: Less than 140 mg/dL
Random blood glucose: Less than 140 mg/dL
Hemoglobin A1c (HbA1c): Less than 5.7% It's essential to note that these ranges may vary slightly depending on the individual and their specific health conditions. For people with diabetes, the American Diabetes Association recommends the following target blood glucose ranges:
Fasting: 80-130 mg/dL 1
Postprandial: Less than 180 mg/dL 1
HbA1c: Less than 7% for most adults 1. Additionally, a normal fasting glucose level is defined as less than 100 mg/dL 2. Some key points to consider are:
Individualization of goals is crucial, taking into account factors such as duration of diabetes, age, comorbid conditions, and hypoglycemia unawareness 1
Postprandial glucose monitoring may be necessary if A1C goals are not met despite achieving preprandial glucose targets 1
Lifestyle modifications, including reducing caloric intake and increasing physical activity, can help improve glucose control and reduce the risk of cardiovascular complications 2

From the Research

The normal blood glucose ranges can be determined by looking at the average glucose levels in healthy, nondiabetic individuals.

The mean average glucose was found to be 98 to 99 mg/dL (5.4 to 5.5 mmol/L) for all age groups except those over 60 years, in whom mean average glucose was 104 mg/dL (5.8 mmol/L) 3.
The median time spent with glucose levels between 70 to 140 mg/dL (3.9 to 7.8 mmol/L) was 96% (interquartile range, 93 to 98) 3.
The median time spent with glucose levels >140 mg/dL was 2.1% (30 min/d), and median time spent with glucose levels <70 mg/dL (3.9 mmol/L) was 1.1% (15 min/d) 3.

Blood glucose targets can be established based on the HbA1c levels.

The average fasting blood glucose needed to achieve predefined HbA1c target levels of 5.5-6.49% (37-47 mmol/mol), 6.5-6.99% (48-52 mmol/mol), 7.0-7.49% (52-58 mmol/mol), 7.5-7.99% (58-64 mmol/mol), and 8.0-8.5% (64-69 mmol/mol) were 122 mg/dL, 142 mg/dL, 152 mg/dL, 167 mg/dL, and 178 mg/dL, respectively 4.
Postmeal blood glucose to achieve the HbA1c level of 6.5-6.99% (48-52 mmol/mol) and 7.0-7.49% (52-58 mmol/mol) were 139 mg/dL and 152 mg/dL, respectively 4.

Glucose monitoring is essential for assessing glycemia over time.

Continuous glucose monitoring (CGM) can provide valuable retrospective data on Time-in-Ranges metrics, the Ambulatory Glucose Profile (AGP), overlay reports, and daily views for persons with diabetes and their healthcare providers 5, 6.
CGM technology and retrospective pattern-based management using various CGM reports have the potential to improve glycemic management beyond what is possible with fingerstick blood glucose monitoring 6.