What is a Continuous Glucose Monitor (CGM)?

A continuous glucose monitor (CGM) is a small, wearable device that tracks your blood sugar levels (also known as glucose) 24 hours a day. It provides real-time information about your glucose levels, including trends and patterns, and can alert you to high (hyperglycemia)  or low (hypoglycemia) glucose. This helps individuals with diabetes better manage their condition by providing more data than traditional finger-prick testing.

Because CGMs provide 24/7 glucose monitoring, it’s possible to measure time in range (TIR) on a continuous glucose monitor (CGM) refers to the percentage of time a person with diabetes spends with their blood glucose levels within a specified target range. It's a key metric for assessing glycemic control and is often used alongside HbA1c to provide a more comprehensive picture of glucose management.  TIR gives insights into glucose fluctuations throughout the day, revealing how diet, exercise, and medication impact blood sugar levels.

What’s the difference between HbA1c and Time in Range (TIR)?

HbA1c reflects average blood glucose over 2-3 months, while TIR focuses on the percentage of time spent within a target glucose range over a period of time (typically a few weeks). TIR offers a more granular view of daily glucose fluctuations, potentially identifying information that might not be picked up by HbA1c (e.g., glucose fluctuations such as hyperglycemia and hypoglycemia).