Core Metrics
- MARD (Mean Absolute Relative Difference)
- The standard metric for CGM accuracy. Represents the average error percentage compared to a lab reference (YSI). Lower is better (e.g., 8.0%).
- ISF (Insulin Sensitivity Factor)
- Also known as Correction Factor. How many mg/dL (or mmol/L) one unit of insulin lowers blood glucose. Used in calculators.
- TIR (Time In Range)
- The percentage of time glucose spends between 70-180 mg/dL (3.9-10.0 mmol/L). The clinical goal is >70%.
- IOB (Insulin On Board)
- Active insulin remaining in the body from previous boluses. Algorithms use decay curves to track this to prevent stacking.
Hardware and System Terms
- AID (Automated Insulin Delivery)
- An umbrella term for systems that modulate pump delivery based on CGM data. Includes commercial closed-loop and DIY systems.
- SMB (Super Micro-Bolus)
- A feature of the Oref1 algorithm (used in AndroidAPS/FreeAPS X) that delivers rapid automatic boluses instead of just increasing basal rates.
- Basal Rate
- The continuous drip of background insulin programmed into a pump, measured in U/hr.
- Cannula
- The small Teflon or steel tube inserted under the skin by an infusion set. See site failures.
Clinical Data
- AGP (Ambulatory Glucose Profile)
- A standardized 14-day data report collapsing glucose data into a single 24-hour visual curve. Found in management platforms like Tidepool.
- HbA1c (Hemoglobin A1c)
- A blood test measuring average glucose over 3 months by analyzing glycated hemoglobin.