The FDA authorized Abbott’s Libre Duo 10 Day Continuous Dual Glucose Ketone Monitoring System on August 25, 2026, creating a new category of wearable diabetes technology. The device is cleared for people aged 2 years and older with diabetes and is the first U.S. wearable designed to continuously monitor ketones, as well as the first device authorized to continuously track both glucose and ketones together.
Libre Duo adds continuous ketone monitoring to the CGM model
Continuous glucose monitors changed diabetes care by replacing isolated finger-stick measurements with a stream of glucose data. Libre Duo extends that model to a second analyte: ketones.
FDA classifies the device as an integrated continuous glucose-ketone monitoring system. It uses a transcutaneous sensor placed into the subcutaneous tissue to measure glucose and ketones in interstitial fluid, with data transmitted to a connected receiver. The authorized system is designed for a 10-day wear period.
That combination matters because glucose and ketones answer different questions. Glucose shows how much sugar is circulating and available for use. Ketones rise when the body shifts toward fat breakdown and can accumulate to dangerous levels when insulin is insufficient.
The clinical concern is diabetic ketoacidosis, not ordinary nutritional ketosis
Diabetic ketoacidosis (DKA) is a potentially life-threatening complication of diabetes caused by severe insulin deficiency. As ketone production rises, the blood can become dangerously acidic. DKA is most strongly associated with type 1 diabetes but can also occur in other forms of diabetes under certain conditions.
The reason continuous ketone information could be useful is timing. A person may have rising ketones before severe symptoms prompt emergency evaluation. FDA says Libre Duo can issue automatic alerts when ketones reach a concerning threshold, potentially giving patients and caregivers earlier warning.
FDA Center for Devices and Radiological Health director Michelle Tarver, M.D., Ph.D., described the clinical rationale directly: “Knowing that ketone levels are rising, and having that information in real time, around the clock, can be the difference between early intervention and a life-threatening emergency.”
That does not mean every increase in ketones represents DKA. FDA specifically states that ketone information should be interpreted together with glucose readings, symptoms, and factors such as eating patterns and exercise.
FDA reviewed six studies involving more than 600 participants
The authorization was based on a clinical and performance program that included six studies enrolling more than 600 participants aged 2 years and older. According to FDA, the studies evaluated glucose and ketone accuracy across a range of concentrations and across the 10-day sensor-wear period.
FDA reported that the device accurately tracked clinically meaningful differences in ketone levels and identified elevated ketones before the onset of DKA. The agency did not describe this as proof that the device prevents DKA in every user. The regulatory conclusion is narrower: the device provided sufficiently reliable glucose and ketone measurements to support authorization for diabetes management under the specified conditions of use.
The De Novo pathway created a new device category
Libre Duo was authorized through FDA’s De Novo pathway rather than a traditional 510(k) clearance. De Novo review is used for novel low- to moderate-risk devices for which there is no legally marketed predicate device of the same type.
FDA assigned Libre Duo De Novo number DEN250049 and created the classification “integrated continuous glucose ketone monitoring system” under regulation 21 CFR 862.1354. Future devices of the same type may be able to use this classification and the associated special controls as a regulatory pathway.
The device had previously received FDA Breakthrough Device designation, a program intended to expedite development and review of technologies that may offer more effective diagnosis or treatment of serious conditions.
Continuous ketone data could add context that glucose alone cannot provide
A glucose reading by itself cannot always tell whether clinically important ketosis is developing. This can matter during illness, missed insulin, pump interruption, prolonged hyperglycemia, or other situations that increase DKA risk.
By putting glucose and ketone trends in the same monitoring system, Libre Duo may reduce the need to wait for symptoms or perform a separate blood or urine ketone test before recognizing that ketones are rising. Whether that translates into fewer emergency visits or fewer DKA admissions will require real-world outcome data after launch.
The distinction between glucose control and broader metabolic state also appears elsewhere in diabetes science. Our GLP-1 drugs explainer reviews how modern therapies alter glucose regulation and appetite, while our tirzepatide mechanism article covers the dual GIP and GLP-1 pathway. Exercise affects glucose handling through yet another mechanism, as discussed in our muscle and diabetes explainer.
The system should not be treated as an autonomous diagnosis of DKA
Continuous sensing can create a temptation to treat every number as a diagnosis. FDA’s language is more cautious. Ketone output should be used together with glucose levels, symptoms, and factors that can influence ketones, including diet and exercise.
Sensor measurements also come from interstitial fluid rather than directly from arterial or venous blood. That distinction is already familiar in continuous glucose monitoring and is one reason symptoms and clinical context still matter when readings appear inconsistent with how a patient feels.
Libre Duo is therefore best understood as an early-warning and monitoring tool, not as a substitute for medical evaluation when DKA is suspected.
What the evidence cannot yet answer
FDA’s authorization establishes that the device met regulatory requirements for safety, performance, and effectiveness as a new device type. It does not yet establish how much continuous ketone monitoring will reduce DKA admissions, emergency-department use, hospitalizations, or mortality in routine practice.
The clinical program was sponsored by Abbott Diabetes Care, the device manufacturer, and the FDA authorization relied on data submitted by the company. Post-market studies and independent real-world analyses will be important for understanding how users respond to ketone alerts and whether continuous ketone monitoring changes clinical outcomes.
Cost, insurance coverage, integration with insulin-delivery systems, alert fatigue, and patient adherence will also influence how much benefit the technology delivers outside controlled studies.
The bigger change is that ketones can now become a continuous signal
The important shift is not simply adding another number to a diabetes app. Until now, ketone testing has usually been intermittent and triggered by symptoms, illness, or high glucose. Libre Duo turns ketones into a continuously monitored signal alongside glucose. If real-world studies show that earlier warning leads to earlier treatment and fewer DKA events, continuous dual-analyte monitoring could become a meaningful new layer of diabetes safety.
References
- U.S. Food and Drug Administration. FDA Authorizes First Wearable Device That Continuously Monitors Both Ketone Levels and Blood Sugar. August 25, 2026. FDA press release.
- U.S. Food and Drug Administration. Libre Duo 10 Day Continuous Dual Glucose Ketone Monitoring System, De Novo DEN250049. Decision date August 25, 2026. FDA De Novo record.