Glycemia Risk Index (GRI)
GRI is one score from 0 to 100 that combines time in the four out-of-range bands, with lows weighted more than highs. Lower is better. It was built in 2022 to match how 330 clinicians ranked 225 CGM tracings. The authors split the score into five zones, A to E, from the best 20% to the worst 20%. (Klonoff et al., the Glycemia Risk Index, 2023)
Formula
GRI = (3.0 × very low %) + (2.4 × low %) + (1.6 × very high %) + (0.8 × high %), capped at 100. Very low is under 54 mg/dL (3.0 mmol/L), low 54–69 (3.0–3.8), high 181–250 (10.1–13.9), very high over 250 (13.9).
(Klonoff et al., the Glycemia Risk Index, 2023)
Worked example
The paper's own example: very low 5%, low 10%, very high 15%, high 20%. Hypoglycemia component = 5 + 0.8 × 10 = 13. Hyperglycemia component = 15 + 0.5 × 20 = 25. GRI = 3.0 × 13 + 1.6 × 25 = 79, zone D, shown as 79·D.
Related terms
Sources, quoted
- Klonoff et al., the Glycemia Risk Index, 2023: “It is calculated as GRI = (3.0 × VLow) + (2.4 × Low) + (1.6 × VHigh) + (0.8 × High), with a maximum permissible value of 100.”
- Klonoff et al., the Glycemia Risk Index, 2023: “Hypoglycemia Component = VLow + (0.8 × Low) (Equation #1) Hyperglycemia Component = VHigh + (0.5 × High) (Equation #2)”
- Klonoff et al., the Glycemia Risk Index, 2023: “The 225 CGM tracings were sorted by average ranking, normalized so that each tracing was assigned a percentile score ranging from 0 to 100, with 0 representing “best” or “no risk” and 100 representing “worst” or “maximum risk.””
- Klonoff et al., the Glycemia Risk Index, 2023: “Using a balanced incomplete block design, 330 clinicians who were highly experienced with CGM analysis and interpretation ranked the CGM tracings from best to worst quality of glycemia.”
- Klonoff et al., the Glycemia Risk Index, 2023: “A set of diagonal lines divides the graph into five glycemia risk zones (which we label A-E) corresponding to the best (first-20th percentile) to worst (81st-100th percentile) quintiles for overall quality of glycemia.”
- Klonoff et al., the Glycemia Risk Index, 2023: “Abbreviations: VLow, <54 mg/dL; <3.0 mmol/L; Low, 54-<70 mg/dL; 3.0-<3.9 mmol/L; CV, coefficient of variation (standard deviation of glucose/mean glucose); VHigh, >250 mg/dL; >13.9 mmol/L; High, >180-250 mg/dL; >10.0-13.9 mmol/L”
Every quote above is checked against its source page before each update of this site; last checked 2026-10-06. The worked example is our own arithmetic. This page explains a term; it is not advice for a person's treatment.