For many years, people with diabetes have used the HbA1c blood test to monitor their average blood sugar levels. However, this test does not show daily changes in glucose that can impact health.
Continuous glucose monitors (CGMs) are now providing a more detailed view. These devices track blood sugar continuously throughout the day and night, giving both patients and doctors more information about fluctuations.
“For years, the medical and patient community relied on single-point glucose checks, whether via a blood test or finger stick capillary blood testing,” said Rodolfo Galindo, M.D., director of the Comprehensive Diabetes Center for the University of Miami Health System. “This approach provided a limited assessment of glucose regulation and changes in humans. Notably, we were not able to acknowledge that until the recent expansion of CGM use in research and clinical practice. With expanded CGM use, we soon realized we knew very little about glucose regulation, patterns, trends and tendencies in humans.”
Unlike traditional finger sticks that provide one measurement at a time, CGMs collect hundreds of readings per day. This allows users to identify patterns such as overnight drops or spikes after meals that might otherwise go unnoticed.
“The use of CGM has helped in early detection of both high and low glucose in patients with diabetes, especially with chronic kidney disorders,” said Ron Varghese, M.D., an endocrinologist with the University of Miami Health System. “Earlier detection of changes in glucose in real time helps patients to prevent low glucose by taking corrective measures at the appropriate time.”
CGMs also avoid some issues that can affect HbA1c results—including anemia, pregnancy, or kidney problems—by providing real-time updates that help detect dangerous highs and lows missed by standard tests.
Research shows people using CGMs often experience improved A1c levels, spend more time within healthy glucose ranges, and have fewer episodes of low blood sugar. Some benefits continue even after stopping device use.
These monitors have proven useful for patients with additional conditions like kidney disease, sleep apnea, gastroparesis, or rare disorders such as insulinoma. They assist with adjusting insulin doses and identifying hidden drops in blood sugar.
“Without a doubt, CGM devices have revolutionized diabetes care and served as a pivotal step into the development of an artificial pancreas,” Dr. Galindo said.
With minute-by-minute tracking from CGMs, patients can better understand how food choices, physical activity, and sleep affect their blood sugar levels.
“The use of CGM and over-the-counter availability of CGM has the potential to detect and transform the care of conditions like prediabetes and sleep disorders and helps to tailor and modify diet in people who can notice changes in glucose in real time with the use of these devices,” Dr. Varghese added.
As technology advances further, continuous monitoring is expected to support more personalized care for people living with diabetes.
