Experts Urge Formal Standards for Continuous Glucose Monitoring Devices to Safeguard Patients

CGM Accuracy Checklist

CGMs are wearable devices which track glucose levels in real-time. They are a popular diabetes management tool, but unlike blood glucose meters, which are governed by ISO standards, there are currently no formal standards for CGM devices.

These organisations are currently developing a new CGM Accuracy Checklist to help people with diabetes, healthcare providers, and medical funders assess whether a CGM is suitable for use, especially among those with insulin-dependent diabetes.

While the checklist does not replace regulatory standards, it helps to fill the gap, providing interim guidance grounded in the best available evidence and developed with technical experts and the diabetes community.

“We’ve seen CGMs being promoted in the wellness world to track how food and lifestyle impact people’s glucose levels.

“But for people living with diabetes, they’re more than just a tool to optimise their health, they are essential for survival. So they need to be accurate,” says Kirsten de Klerk, co-founder of SA Diabetes Advocacy and a person living with Type 1 diabetes.

Compensating for uncertainty

Currently, many are using CGMs alongside other trusted devices or traditional finger-prick tests to compensate for the uncertainty.

Ensuring devices meet clear, evidence-based standards that are publicly available and locally relevant before being sold would remove this additional burden.

CGMs empower people to manage their diabetes, but greater reliance on these devices requires better accuracy standards because of the serious consequences of an inaccurate reading.

Chantal dos Santos’ young son was diagnosed with Type 1 diabetes four years ago.

In January 2024, he was admitted to the ICU with Diabetic Ketoacidosis – a life-threatening diabetes complication.

“We had been using a continuous glucose monitor that had consistently given inaccurate readings.

“When we raised our concerns with the distributors, we were made to feel as if the fault lay with us, not the device.

“It was only after researching more that I realised some medical devices may not be properly tested before reaching families like ours. That’s terrifying,” Dos Santos says.

Dr Michelle Carrihill, paediatric endocrinologist at the Red Cross Children’s Hospital, says, “accuracy isn’t a luxury, it’s essential”.

“I rely on CGMs to help children, young people and their families manage diabetes safely, but that only works if the data is accurate.

“We make real-time decisions based on those numbers, from how much insulin to give to whether it’s safe for a child to go to school or sleep through the night.

“If a CGM isn’t reliable, it puts lives at risk. Doctors and families need to know that these devices have been properly tested and that they work in real life, not just in a lab,” Carrihill says.

Cathy Haldane, head of the non-communicable disease (NCD) programme at FIND, says, “Many people assume that if a CGM is available on the market, it must be accurate, but that’s not always true.

“Not all CGMs are tested in ways that reflect real-life use, especially for people who use insulin and experience fast-changing glucose levels.”

She adds, “People living with diabetes should have access to clear, independent information about how these devices really perform.

"In the absence of global standards, the CGM Performance Factsheet is designed to support more informed, safer choices because everyone deserves tools they can trust.”

A dilemma

International efforts are underway to define safety standards for CGMs, but in the interim, accuracy must be carefully evaluated through transparent, clinical evidence.

While more affordable CGM devices are entering the market is an exciting development in South Africa, SA Diabetes Advocacy is clear: affordability can never come at the cost of quality or safety.

“Some CGM devices have not been extensively tested, especially on people living with diabetes who are insulin dependent, or study results were not peer-reviewed or publicly available, so it’s impossible to tell if these devices are truly effective,” De Klerk says.

This creates a dilemma, especially in low-resource communities: Lower prices are driving adoption, and without regulatory oversight, people may end up trusting devices that haven’t been proven safe or effective.

Clear, transparent comparisons backed by peer-reviewed data will enable better decisions and prevent dangerous assumptions based on marketing claims alone.

South Africa can take guidance from similar efforts to manage standards for CGM devices internationally.

In the United Kingdom, for example, the Diabetes Specialist Nurse Forum published a comparison chart of CGMs to help users make decisions based on clinical evidence, regulatory status and user experience.

Medical technology has the power to improve lives – but only when it’s safe, reliable and tested correctly.

In the case of CGMs, accuracy isn’t just a technical detail; it’s a life-saving requirement.

“As the global regulatory landscape evolves, tools like the checklist help ensure that people have access to the best available information, even in the absence of binding international standards,” Haldane concludes.