Toolbox
Ketone Level Interpreter
What your ketone reading actually means — nutritional ketosis, therapeutic targets, and the critical line between adaptation and emergency.
Your reading
mmol/L
Blood BHB is the most accurate measure of current ketone levels. (Urine strip support coming in a follow-up — they show falsely low readings after keto-adaptation, so blood BHB is the recommended modern method.)
Medications that may affect your result
SGLT2 inhibitors (empagliflozin, dapagliflozin, canagliflozin) can cause euglycemic diabetic ketoacidosis — elevated ketones with normal blood glucose. If you are on an SGLT2 inhibitor and your BHB is above 3 mmol/L, contact your provider promptly even if your glucose is normal.
Insulin therapy in type 1 diabetes can lead to DKA when insulin is missed or under-dosed. Any reading above 1.5 mmol/L in a person with type 1 diabetes warrants checking glucose and following your sick-day management plan.
Corticosteroids (prednisone, dexamethasone) elevate blood glucose and can complicate ketone interpretation during fasting or low-carb eating.
If you are taking any of these medications, your interpretation changes — discuss ketone monitoring targets with your prescribing provider.
About this tool
Formula
Blood BHB (β-hydroxybutyrate) is measured directly from a fingerstick blood meter, reported in mmol/L. No formula — the value is read off the meter.
Classification
Baseline (not in ketosis): below 0.5 mmol/L. Light ketosis: 0.5–1.0. Nutritional ketosis: 1.0–3.0 (the target zone for most people following a ketogenic diet). Deep ketosis: 3.0–5.0 (extended fasting or therapeutic protocols). Seek review: 5.0 and above (DKA risk, especially for type 1 diabetes or SGLT2 inhibitor users).
Known Limitations
Blood BHB measures one of three ketone bodies (the dominant circulating ketone). Urine acetoacetate strips and breath acetone analyzers measure different ketones with different reliability profiles — blood BHB is the gold standard for assessing current ketosis. After keto-adaptation (4–8 weeks), BHB levels often settle into the 0.5–1.5 range as the body uses ketones more efficiently; this is a sign of adaptation, not a loss of ketosis. Acute illness, intense exercise, or extended fasting can transiently elevate BHB.
Sources
Volek JS, Phinney SD. The Art and Science of Low Carbohydrate Living. Beyond Obesity, 2011. Newman JC, Verdin E. β-Hydroxybutyrate: A Signaling Metabolite. Annual Review of Nutrition, 2017. American Diabetes Association. Standards of Medical Care in Diabetes. Diabetes Care.
Educational tool only. Not for diagnostic purposes. Consult a healthcare provider for medical decisions.