Standard Deviation of Glucose(SD)
Definition
A statistical measure of how widely glucose values are spread around the mean glucose over a given period. A lower standard deviation indicates more stable glucose with smaller fluctuations, while a higher SD reflects wider swings between highs and lows. For most adults with diabetes, an SD below one-third of the mean glucose is considered a reasonable target. SD is used alongside the coefficient of variation (CV = SD ÷ mean × 100) to assess glycemic variability from CGM data.
Why “Standard Deviation of Glucose” Matters for Glucose Monitoring
Understanding standard deviation of glucose is essential for anyone using or evaluating a continuous glucose monitor. This concept directly affects how CGM devices are designed, how glucose data is interpreted, and how clinical decisions about blood sugar management are made. CGM metrics transform thousands of raw glucose readings into actionable numbers that clinicians use to assess glucose control, adjust medications, and set treatment goals.
This term applies broadly across all continuous glucose monitors and is foundational knowledge for interpreting CGM data, whether you are managing diabetes or using a sensor for metabolic wellness.
Related Terms
A standardized measure of glucose variability calculated as the standard deviation of glucose values divided by the mean glucose, multiplied by 100, expressed as a percentage.
The magnitude and frequency of blood glucose fluctuations over a defined period.
The arithmetic average of all glucose readings over a specified period, calculated from the 288 or more daily readings that most CGMs capture (one reading every 5 minutes).
A composite score that combines the standard deviation and mean glucose of CGM data to quantify overall glycemic instability on a single scale.