Q: I’ve heard about “time in range” as a new way to monitor blood sugar levels over time. Is this a substitute for the A1C test? How can we start tracking and improving my son’s time in range?
A: Continuous glucose monitoring (CGM) technology gives people with diabetes ample data about how their blood sugar levels change throughout the day. Time in range (TIR) is a way of using this data to measure the percentage of time that blood sugar levels stay within a goal range. For example, a target TIR for a child or teen might be 60 percent, which means that at least 60 percent of CGM readings taken within a 24-hour period fall between a range of, say, 70 and 180 mg/dl.
Your child’s diabetes care team can use TIR as an important augment to hemoglobin A1C results, but not as a substitute. Let’s say that at your child’s three-month checkup with their pediatric endocrinologist, their A1C result was 7. Having access to TIR data can help give this A1C much greater context. Was that 7 the result of a mix of lots of lows and highs, or was it the result of the majority of blood sugar level readings being in the goal range? TIR helps to provide a clearer answer of how well diabetes is controlled.
If your child uses CGM, you can discuss with your care team what an appropriate target parameter for TIR might be. Once you have these TIR targets, you and your child can work together to see how different activities affect blood sugar levels and insulin needs, and discuss with your care team how to make adjustments to reach TIR goals. Normal childhood height and weight gain, puberty, and how much kids exercise, along with what they are eating, will all affect insulin needs, so insulin regimens need to be reviewed and adjusted on a regular basis. Use your care team as a source of feedback and help for troubleshooting and making adjustments to move closer to a goal TIR.
For children with diabetes not using CGM, parents may wonder if TIR can still work with a glucometer. Monitoring with a glucometer cannot give as complete a picture as CGM, because there are far fewer blood sugar readings. But glucometer tracking can still provide important snapshots into your child’s typical range. Blood sugar data can be reviewed every two to four weeks, with attention paid to the proportion of readings that fall within the target range determined by the child’s care team. Regardless of whether you’re monitoring blood sugar by CGM or glucometer, adhering to your child’s diabetes regimen and frequent communication with your care team are key to achieving good diabetes management.