Diabetes Dialogue: FreeStyle Libre Duo Cleared for Ketone Monitoring

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Diabetic ketoacidosis remains a leading cause of preventable hospitalization in diabetes care, yet ketone testing has lagged far behind glucose monitoring in both accuracy and adoption. Continuous ketone monitoring aims to close this gap, giving clinicians and patients a real-time window into a metabolic state that urine strips and intermittent blood testing have rarely captured well.

On a recent episode of Diabetes Dialogue, hosts Diana Isaacs, PharmD, and Natalie Bellini, DNP, spoke with Eden Miller, DO, founder of Diabetes and Obesity Care, and Davida Kruger, NP, of Henry Ford Health, about the FDA clearance of the FreeStyle Libre Duo (Abbott), a combined glucose and ketone sensor. Both guests served on the international advisory board contributing to the sensor's development and co-authored related work in The Lancet.

The sensor pairs a 10-day wear with a 1-hour warm-up and reports glucose and beta-hydroxybutyrate readings every minute through the existing Libre app. Direct beta-hydroxybutyrate tracking offers an earlier signal than urine ketone testing, which measures acetoacetate and lags physiologic change. Ketone values <0.6 mmol/L default to a glucose-focused display, values between 0.6 and 3.0 mmol/L trigger a trend view with directional arrows, and a fixed threshold of 3.0 mmol/L generates an urgent high alert.

Guests emphasized glucose and ketone levels do not always move together. Pump-suspension research led by Jennifer Sherr, MD, PhD, at Yale, showed considerable variability in time to ketosis, with some patients developing ketosis within 4 hours of an interruption and others remaining ketone-free well beyond it. This variability carries particular relevance for patients using sodium-glucose cotransporter-2 (SGLT2) inhibitors off-label in type 1 diabetes, since euglycemic ketosis can develop without corresponding hyperglycemia.

At launch, the sensor is expected to pair with select automated insulin delivery systems, including Beta Bionics' iLet, with expanded compatibility anticipated for Omnipod 5 and Medtronic's Instinct sensor into 2027, though no pump algorithm will adjust dosing based on ketone data yet. Coverage will begin through commercial insurance only, without Medicare or Medicaid reimbursement established at this time. Clinicians will need updated protocols to interpret ketone trend arrows manually, distinguishing benign nutritional ketosis from evolving decompensation before automated support becomes available.

Continuous ketone monitoring marks a shift comparable to the early adoption of continuous glucose monitoring, when clinicians needed guidance interpreting new, high-frequency physiologic data. As real-world experience accumulates over the coming year, the technology is positioned to inform individualized ketone thresholds, refine detection of infusion-set failure, and potentially reduce emergency care tied to diabetic ketoacidosis.

Editors’ Note: Isaacs reports disclosures with Dexcom, Abbott, Lilly, Novo Nordisk, Medtronic, Insulet, and others. Bellini reports disclosures with Abbott Diabetes Care, MannKind, Povention Bio, and others. Kruger reports disclosures with Abbott, CeQur Corporation, Embecta, Eli Lilly, MannKind, Medtronic, and others. Miller reports disclosures with Abbott, Bayer, Corcept, Eli Lilly, Insulet, Novo Nordisk, and others.

References

1. U.S. Food and Drug Administration. FDA authorizes first wearable device that continuously monitors both ketone levels and blood sugar. Published August 25, 2026. Accessed August 25, 2026. https://www.fda.gov/news-events/press-announcements/fda-authorizes-first-wearable-device-continuously-monitors-both-ketone-levels-and-blood-sugar