Plain-English definitions of the continuous glucose monitoring and metabolic-health terms that show up across our guides. Educational only, not medical advice.
An umbrella term for abnormal glucose regulation that doesn't yet meet the threshold for diabetes, including impaired fasting glucose, impaired glucose tolerance, and high glucose variability.
Read more →A blood test reflecting average glucose over roughly the prior 2–3 months, reported as a percentage. Useful, but it hides the day-to-day highs and lows that shape risk.
HbA1c vs CGM →An HbA1c expressed on the everyday glucose scale (mg/dL or mmol/L), so it's easier to compare with a meter or CGM reading. Derived from the ADAG study formula.
Calculator →An estimated, lab-like A1c calculated from the mean glucose a CGM measures over 14+ days. Because it comes from CGM data, GMI can differ from a blood HbA1c.
Read more →The percentage of time glucose stays within a target band (commonly 70–180 mg/dL) on a CGM. A target of >70% is common for many adults with diabetes.
Read more →How much glucose swings around its average, often measured as coefficient of variation (CV). High variability is linked to oxidative stress and is a target of good glucose control.
Read more →A measure of glucose variability: the standard deviation divided by the mean glucose. A CV at or below 36% is a commonly cited marker of stable glucose.
A natural early-morning rise in glucose driven by overnight hormones, often seen as a climb in the hours before waking on a CGM trace.
Read more →A drop in glucose that occurs a few hours after eating, sometimes causing shakiness, sweating, or fatigue. CGM can help reveal the pattern.
Read more →Glucose that is higher than normal but below the diabetes threshold, one part of the broader dysglycemia spectrum, and often responsive to lifestyle change.
CGM for prediabetes →A fasting glucose above the normal range but below the diabetes cutoff, one of the states grouped under prediabetes.
Glucose that stays elevated too long after a glucose challenge (or a meal), another form of prediabetes, and a marker of early insulin resistance.
A small wearable sensor that samples glucose throughout the day and night, producing a continuous trace rather than isolated finger-stick readings.
A standardized one-page CGM report that overlays several days of glucose into a single daily picture, making patterns easier to read.
Low blood glucose, commonly flagged below 70 mg/dL (3.9 mmol/L), with a more serious level below 54 mg/dL (3.0 mmol/L). Severe lows need prompt treatment.
High blood glucose, commonly flagged above 180 mg/dL (10.0 mmol/L). Sustained highs over time contribute to complications.
The glucose response after eating. Sharp post-meal spikes can occur even when fasting values and HbA1c look acceptable.
A metabolic phenotype defined by the shape of a person's glucose curve rather than an average, for example, stable, post-meal spiker, or variable.
Clinically reviewing device data, such as CGM readings, between visits. Under Medicare it maps to specific CPT codes.
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