Which statement about CGM accuracy is true regarding MARD?

Which statement about CGM accuracy is true regarding MARD?

• A. Lower MARD indicates higher CGM accuracy
• B. Higher MARD indicates higher CGM accuracy
• C. MARD has no relation to accuracy
• D. MARD only measures time device worn

Answer: (A)

The main idea here is that MARD measures how closely CGM readings match a reference glucose value. It’s the mean of the absolute differences between the CGM and the reference, expressed as a percentage of the reference value. Because it’s an average of how far off the CGM readings are, a smaller number means the CGM is closer to the true value, i.e., more accurate. So why is the statement the best one? If the MARD is lower, the readings tend to align more closely with the reference measurements, indicating higher accuracy. Conversely, a higher MARD means larger average discrepancies. MARD is about accuracy, not about how long the device is worn or any other factor, and it doesn’t imply perfect performance in every situation (some devices may perform differently at very low glucose levels, for example).

The main idea here is that MARD measures how closely CGM readings match a reference glucose value. It’s the mean of the absolute differences between the CGM and the reference, expressed as a percentage of the reference value. Because it’s an average of how far off the CGM readings are, a smaller number means the CGM is closer to the true value, i.e., more accurate.

So why is the statement the best one? If the MARD is lower, the readings tend to align more closely with the reference measurements, indicating higher accuracy. Conversely, a higher MARD means larger average discrepancies. MARD is about accuracy, not about how long the device is worn or any other factor, and it doesn’t imply perfect performance in every situation (some devices may perform differently at very low glucose levels, for example).