Calibration
Definition
The process of verifying and adjusting CGM accuracy by comparing a sensor reading against a traditional fingerstick blood glucose measurement. Older CGM systems required 2 calibrations per day, but most modern devices — including the Dexcom G7 and FreeStyle Libre 3 — are factory-calibrated at the manufacturing facility and require zero fingerstick calibrations during use. The Eversense E3 still requires 1 calibration per day for optimal accuracy.
Why “Calibration” Matters for Glucose Monitoring
Understanding calibration is essential for anyone using or evaluating a continuous glucose monitor. This concept directly affects how CGM devices are designed, how glucose data is interpreted, and how clinical decisions about blood sugar management are made. The technical foundations of CGM technology determine the accuracy, reliability, and user experience of every device on the market — from the Dexcom G7 to over-the-counter options like the Abbott Lingo.
This term is particularly relevant to 3 CGM products in our database. Understanding calibration helps you compare devices more effectively and choose the right continuous glucose monitor for your specific needs.
Related Terms
A wearable medical device that tracks glucose levels in interstitial fluid 24 hours a day through a tiny sensor inserted just under the skin.
Mean Absolute Relative Difference, the gold standard metric used to evaluate CGM sensor accuracy.
The required initialization period after inserting a new CGM sensor before it begins delivering glucose readings.
The fluid that surrounds cells in body tissue, where CGM sensors measure glucose concentration.