Insulin Pump Therapy: Who, Why, and How

Q What are CGMs, and are they required?

CGMs are small, external devices that sample glucose from the interstitial fluid using an electrode under the skin. The electrode transmits information to a display device, which can alert patients of patient-specific glucose values: if a high or low glucose value is reached; if the glucose value is predicted to change; or the rate of glucose value change.

CGMs do not completely replace testing glucose levels, as they typically need to be calibrated two or more times throughout the day (though upcoming technology may reduce that to one or no calibrations). During calibration, patients manually check their glucose levels and enter readings into the CGM to ensure accuracy.

CGMs are not required, but they can enhance a patient’s insulin pump experience. Some CGMs “talk” directly with insulin pumps, so users do not have to manually input glucose levels. However, while there is even a CGM on the market that allows insulin dosing without a finger-prick, most sensors encourage patients to dose insulin based on manual glucose readings rather than CGM readings. A notable exception is a CGM “talking” to an insulin pump with a safety feature that can temporarily shut off the pump if low glucose levels are detected or predicted.^16-18