What are continuous blood glucose monitors (CGMs)?

Updated: Jan 22, 2020
  • Author: Benjamin Daniel Liess, MD; Chief Editor: George T Griffing, MD  more...
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A continuous blood glucose monitor (CGM) assesses blood glucose levels on a near-continuous basis. A typical system consists of a glucose sensor placed subcutaneously, a non-implanted transmitter, and a receiver worn like a pager, which records blood glucose levels at frequent intervals and monitors trends.

CGM systems monitor interstitial fluid glucose levels. They must be calibrated with traditional fingerstick tests.

Continuous monitoring provides documentation of blood glucose response to insulin dosing, eating, exercise, and additional influences. Overnight monitoring may identify problems with insulin dosing and allow adjustments of basal levels. Many units are equipped with alarms to warn patients of hyperglycemia or hypoglycemia and provide time for treatment.

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