Table 1.
Key metrics for CGM data analysis and reporting
| CGM metric | Measures | ATTD consensus |
|---|---|---|
| 1 | Mean glucose | √ (calculated) |
| Severe hypoglycemia* | Clinical diagnosis: event requiring assistance (level 3) | |
| Percentage of time in hypoglycemic ranges, mg/dL (mmol/L) | ||
| 2 | Clinically significant/very low/immediate action required | <54 (<3.0) (level 2) |
| 3 | Alert/low/monitor | <70–54 (<3.9–3.0) (level 1) |
| Percentage of time in target range, mg/dL (mmol/L) | ||
| 4 | Default | 70–180 (3.9–10.0) |
| Secondary | 70–140 (3.9–7.8) | |
| Percentage of time in hyperglycemic ranges, mg/dL (mmol/L) | ||
| 5 | Alert/elevated/monitor | >180 (>10) (level 1) |
| 6 | Clinically significant/very elevated/immediate action required | >250 (>13.9) (level 2) |
| Diabetic ketoacidosis* | Clinical diagnosis: ketones, acidosis, and usually hyperglycemia (level 3) | |
| Glycemic variability | ||
| 7 | Primary glycemic variability | CV |
| Stable | CV <36%, | |
| Unstable | CV ≥36% | |
| Secondary glycemic variability | SD | |
| 8 | eA1C | √ (calculated) |
| 9 | Three time blocks: sleep, wake, 24 h | 12:00 a.m.–6:00 a.m., 6:00 a.m.–12:00 a.m., 12 a.m.–12:00 a.m. |
| Recommended data sufficiency | ||
| 10 | Collection period (minimum no. of weeks) | 2 |
| 11 | Percentage of expected CGM readings (minimum percentage) | 70–80 (10 of 14 days) |
| 12 | Episodes of hypoglycemia/hyperglycemia (minimum no. of minutes) (with beginning and end of episode defined) | 15 min |
| 13 | Area under the curve | √ (calculated) |
| 14 | Risk of hypoglycemia and hyperglycemia | LBGI/HBGI recommended |
| 15 | Standardized CGM visualization of data | AGP recommended |
*
Severe hypoglycemia (level 3) and diabetic ketoacidosis (level 3) are not key CGM metrics per se. However, these conditions are included in the table because they are important clinical categories that must be assessed and documented.