Federal regulators have authorized the first wearable sensor in the United States that continuously tracks ketone levels, and the first anywhere that measures ketones and blood sugar from a single device. The Food and Drug Administration authorized Abbott's Libre Duo 10 Day Continuous Dual Glucose Ketone Monitoring System for people with diabetes aged 2 years and older.
The decision matters most to a specific group of households: families where someone uses insulin, where someone takes a newer class of diabetes medicine known as an SGLT2 inhibitor, or where a child has type 1 diabetes and a parent has spent years guessing whether a stomach bug is just a stomach bug. Until now, checking ketones meant a urine strip or a fingerstick, and each test produced a single number with no sense of direction.
An estimated 40.1 million Americans live with diabetes, according to Centers for Disease Control and Prevention figures the FDA cited in announcing the authorization. Only a subset face meaningful ketone risk, but for that subset the consequence is diabetic ketoacidosis, a complication that can escalate from mild nausea to an emergency department admission within hours.
Rising Ketones Can Outrun a Normal Glucose Reading
The clinical problem the device targets is a mismatch that continuous glucose monitors alone cannot catch. Ketones build up when the body burns fat rather than glucose for fuel, and they do not always track with blood sugar. A person can have ketones climbing toward a dangerous range while their glucose reading looks unremarkable.
That gap is sharpest among people taking SGLT2 inhibitors, a widely prescribed class of medicines that lower blood sugar by promoting glucose excretion in the urine. Those drugs have been associated with ketoacidosis occurring at near-normal glucose levels, which means the number a patient trusts most can look reassuring while the actual risk is rising. A Lancet review of expert recommendations on continuous ketone monitoring points to the rise in so-called euglycemic ketoacidosis as a central reason the technology has drawn clinical interest.
Early ketoacidosis symptoms often resemble the flu, which is part of why the condition gets missed at home. Nausea, fatigue, and stomach pain are easy to attribute to a virus, especially in a child.
The sensor measures both glucose and ketones in the fluid just under the skin, once per minute, across a 10-day wear period. Readings travel wirelessly to a compatible smartphone, showing current values and whether they are trending up or down, according to a clinical summary of the authorization. Abbott says the system sends an alert via its mobile app when ketone levels begin to rise.
Inside the Evidence Behind the Authorization
The FDA reviewed the device through the De Novo pathway, which is used for novel low- to moderate-risk device types that have no existing equivalent on the market. The agency had earlier granted the system breakthrough device designation, a program meant to expedite the review of technologies for life-threatening conditions. Abbott submitted accuracy data from six clinical studies enrolling more than 600 participants aged 2 and older.
Those studies evaluated how well the sensor tracked glucose and ketone concentrations across a wide range of values. The agency reported that the device accurately tracked clinically meaningful changes in ketone levels throughout the full wear period, including identifying elevated ketones before ketoacidosis set in. Along with the authorization, the FDA established special controls covering labeling and performance testing for this new device category.
Michelle Tarver, director of the FDA's Center for Devices and Radiological Health, said in the announcement that having real-time ketone information "can be the difference between early intervention and a life-threatening emergency."
What the studies measured was accuracy, not outcomes. The clinical program did not demonstrate that wearing the sensor reduces hospital admissions, emergency visits or deaths from ketoacidosis. That distinction matters when weighing whether the device is worth adding to an already expensive routine.
How broadly continuous ketone monitoring is needed remains an open question in the field. As Medscape noted in its coverage, the need has been debated in diabetes circles, with some specialists pointing to the value of heading off progression to ketoacidosis and of making SGLT2 inhibitors safer to use.
Families Managing Type 1 Diabetes Face the Sharpest Decisions
The inclusion of children as young as 2 is the part of this authorization most likely to change how a household operates. Very young children cannot describe early ketoacidosis symptoms, and caregivers are left interpreting fussiness, refusal to eat, and lethargy without a reliable signal.
Parents of children with type 1 diabetes, adults using insulin pumps, people with type 2 diabetes who take SGLT2 inhibitors, and anyone with a history of recurrent ketoacidosis are the groups most likely to benefit. People with type 2 diabetes managed on metformin alone, without insulin, generally face far lower ketone risk and are not the intended audience.
The device works with the current Libre app and is designed to be compatible with automated insulin delivery systems, according to Abbott's announcement of the authorization. The company has said it plans to connect the system to two pump platforms by the end of this year and to several others the following year, so households already using a pump-and-sensor combination should confirm the timing for their specific device.
Cost and Availability Remain the Open Questions
Abbott plans to launch the system in the United States later this year. No pricing has been announced, and no insurer coverage decisions have been published. That leaves the most practical household question unanswered.
Coverage for continuous glucose monitoring has expanded substantially under Medicare and most commercial plans, but the ketone-sensing function is new, and no established billing pathway exists yet. Patients should expect a period during which coverage varies by plan and state Medicaid program.
Anyone currently managing ketone risk should not change their routine based on this announcement. Existing urine and blood ketone testing remains the standard, and no clinical guideline has been revised. People who use insulin or SGLT2 inhibitors can ask their diabetes care team whether continuous ketone monitoring would add value in their specific case and whether their plan is likely to cover it once the product becomes available at pharmacies. A pharmacist-focused summary of the authorization is a useful starting point for those conversations.
Anyone with vomiting, deep or rapid breathing, confusion, or fruity-smelling breath should seek urgent medical evaluation regardless of what any device is displaying.
Key Questions Answered
What did the FDA actually authorize? The agency authorized the Libre Duo 10 Day Continuous Dual Glucose-Ketone Monitoring System for people aged 2 and older with diabetes. It is the first US wearable to continuously monitor ketones and the first to combine ketone and glucose sensing in one device.
Why does tracking ketones matter separately from blood sugar? Ketones and glucose do not always move together. Ketones can rise to dangerous levels while a glucose reading still looks normal, a known risk with SGLT2 inhibitor medicines.
Who benefits most from this device? People who use insulin, people taking SGLT2 inhibitors, young children with type 1 diabetes, and anyone with a history of repeated ketoacidosis episodes.
Can it be bought right now? No. Abbott has said it plans to launch in the United States later this year. Pricing and insurance coverage have not been announced.
Does this replace fingersticks or urine ketone strips? Not currently. Existing urine and blood ketone testing remains standard practice, and no clinical guidelines have been revised as a result of this authorization.
What symptoms should prompt urgent care? Vomiting, rapid or deep breathing, confusion, severe abdominal pain, or fruity-smelling breath warrant immediate medical evaluation. Early ketoacidosis can resemble the flu.
Did the studies prove it prevents hospital admissions? No. The six clinical studies assessed measurement accuracy in more than 600 participants. They were not designed to show reductions in emergency visits, admissions, or deaths.
