Which CGM target range is used for time-in-range?

• A. 60-140 mg/dL
• B. 100-180 mg/dL
• C. 70-180 mg/dL
• D. 80-160 mg/dL

Answer: (C)

Time in range is defined as the percentage of time a person’s glucose readings fall within a chosen target window. For CGM-based TIR, the standard target window is 70 to 180 mg/dL. This range is used because it safely excludes lows that risk hypoglycemia (below 70) and highs that indicate hyperglycemia (above 180) while still covering most typical daily fluctuations. Using 70–180 mg/dL as the benchmark aligns with widely accepted diabetes care guidelines and provides a practical balance to improve long-term outcomes.

The other ranges are less suitable as universal TIR targets because they either tighten the window too much or shift it in a way that excludes many normal or acceptable readings, making them less representative for calculating time in range.