A Second Number That Could Matter During a Diabetes Emergency
A continuous glucose monitor can show a reassuring number while a serious problem is developing. In some people with diabetes, ketones rise even when glucose is not unusually high. Conventional glucose sensors cannot detect that change. On August 25, 2026, the US Food and Drug Administration (FDA) authorized Abbott’s Libre Duo 10 Day, a wearable that measures glucose and ketones with a single sensor.
Instead of waiting for someone to use a separate ketone test, the device tracks both readings throughout the day and night. That could be particularly useful when illness or an insulin pump problem makes ketone levels harder to anticipate.
Why Glucose Alone Can Miss the Warning
Diabetic ketoacidosis (DKA) can develop when the body does not have enough insulin. It begins breaking down more fat for energy, producing ketones that can build up and make the blood dangerously acidic. Symptoms may include vomiting, stomach pain, deep or rapid breathing, and severe tiredness. Without prompt treatment, DKA can be life-threatening. It is more common in type 1 diabetes but can also occur in type 2.
Glucose is often high during DKA, but not always. People taking SGLT2 inhibitors, a class of diabetes medicines, can develop ketoacidosis without the very high glucose readings they might expect. Illness, eating less than usual, or interrupted insulin delivery can also make the situation harder to judge from glucose alone.
That is why diabetes care plans often call for ketone checks during illness, sustained high glucose, or suspected pump failures. The problem is that blood and urine ketone tests only provide a result when someone stops to perform one.
What the Dual Sensor Changes
Libre Duo 10 Day measures glucose and beta-hydroxybutyrate, the main ketone doctors look at when assessing DKA risk, in fluid just beneath the skin. It updates readings every minute and sends them wirelessly to a compatible smartphone. The Libre app displays current values and trends and can issue alerts when ketones reach concerning levels. In the United States, the system is intended for people with diabetes aged two years and older, with each sensor designed to last up to ten days.
A standard continuous glucose monitor shows glucose changes but not ketones. Blood ketone meters require a finger prick and a test strip; urine strips offer a less immediate picture of ketone levels. Both types of test capture a particular moment. Continuous monitoring makes it possible to see whether ketones are rising, steady, or falling between those checks.
For example, a rising ketone trend after a suspected insulin pump failure may prompt someone to follow their prescribed sick-day or pump-failure plan. The reading still needs to be considered alongside glucose levels and symptoms rather than treated as a diagnosis on its own.
What the FDA Studies Actually Showed
The FDA authorized Libre Duo through its De Novo review process for new types of medical devices. The clinical program included six studies involving more than 600 people aged two and older. According to the agency, the findings supported the accuracy of both glucose and ketone measurements and showed that the sensor could track meaningful ketone changes across its ten-day wear period.
These studies addressed how well the device measures and detects changes, not whether using it reduces episodes of DKA or hospital admissions. A reduction in those outcomes has not yet been established in the FDA authorization evidence. It is also important to distinguish high ketones from DKA itself: diagnosing DKA requires medical assessment, including checking for excess acid in the blood.
Who Might Benefit, and Where Caution Is Needed
People with type 1 diabetes who use insulin pumps may have a particular reason to consider continuous ketone monitoring. A disconnected infusion set or blocked cannula can interrupt insulin delivery unexpectedly. Parents of young children with diabetes may also appreciate having ketone information without needing to perform another finger-prick test when a child is ill.
Some people with type 2 diabetes, including those who use insulin or take SGLT2 inhibitors, may face situations where ketone monitoring is useful. The decision depends on individual risk, previous DKA episodes, current treatment, and the ability to respond to readings. Abbott also plans data sharing through LibreLinkUp for caregivers and LibreView for clinicians, although shared readings do not mean someone is monitoring them at every moment.
The alarms have important limits. Abbott warns that the Urgent High Ketones alarm may miss some readings above 3.0 mmol/L, and that the Urgent Low Glucose alarm may miss some glucose readings below 55 mg/dL. Users should look at the sensor values as well as the alerts. If glucose readings or alarms do not match how they feel, Abbott advises using a finger-stick blood glucose meter for treatment decisions.
Ketones may also rise during fasting or prolonged strenuous exercise, so an elevated value does not necessarily mean DKA. On the other hand, vomiting, deep or rapid breathing, confusion, or a marked decline in condition warrants urgent medical assessment, regardless of what the display shows. The person’s diabetes team should set out what to do at different ketone levels.
Ten-Day Wear Does Not Always Mean Ten Full Days
Sensor life is another practical limitation. In Abbott’s wear-duration study, 84.1% of sensors used by adults and 68.8% of those used by children lasted the full ten days. Roughly three in ten pediatric sensors therefore stopped short of the maximum wear period. Families may need to plan for early replacement, particularly when uninterrupted monitoring matters.
The phone-based system also requires a compatible device, correct setup, and a reliable connection. A detached sensor, lost connection, or disabled notification could interrupt the information a user expects to receive.
Prescription, Availability, and Pump Compatibility
Libre Duo 10 Day is a prescription-only medical device in the United States, as the FDA’s classification order explicitly states. Authorization on August 25 did not mean it was immediately available to buy. Abbott announced plans for a US launch later in 2026, and its US product page was still describing the device as coming soon in October. The cited company materials did not specify a retail price or comprehensive insurance coverage. Prescription access, replacement sensors, and reimbursement will all affect the cost of regular use.
Europe has a separate regulatory arrangement. On May 27, 2026, Abbott announced CE marking for two versions: Libre Duo 10 Day for people aged two and older, and a Libre Duo model designed to last up to 15 days for adults aged 18 and older. Abbott said it planned launches in selected European countries, not an immediate rollout across the region.
Abbott is also developing connections with automated insulin delivery systems. In its August announcement, the company projected compatibility with the iLet and twiist systems by the end of 2026, with additional integrations involving other pump manufacturers targeted for 2027. Those dates are plans, not a guarantee that every pump will work with Libre Duo at launch.
References
- Abbott. (2026, May 27). Abbott secures CE Mark for world’s first dual glucose-ketone sensing technology for people with diabetes. Abbott MediaRoom.
- Abbott. (2026, August 25). Abbott receives FDA authorization for world’s first dual glucose-ketone sensing technology for people with diabetes. Abbott MediaRoom.
- Abbott. (n.d.). Libre Duo 10 Day: Product information and important safety information. FreeStyle Libre US.
- Kong, Y. W., Morrison, D., Lu, J. C., Lee, M. H., Jenkins, A. J., & O’Neal, D. N. (2024). Continuous ketone monitoring: Exciting implications for clinical practice. Diabetes, Obesity and Metabolism, 26(Suppl. 7), 47–58. https://doi.org/10.1111/dom.15921.
- Reuter, E. (2026, August 19). 5 questions on Abbott’s glucose-ketone sensors. MedTech Dive. Read article.
- Umpierrez, G. E., et al. (2024). Hyperglycemic crises in adults with diabetes: A consensus report. Diabetes Care, 47(8), 1257–1275. https://doi.org/10.2337/dci24-0032.
- U.S. Food and Drug Administration. (2026, August 25). FDA authorizes first wearable device that continuously monitors both ketone levels and blood sugar. FDA news release.
- U.S. Food and Drug Administration. (2026, August 26). Libre Duo 10 Day Continuous Dual Glucose Ketone Monitoring System (De Novo DEN250049): Classification order. FDA classification order (PDF).