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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