Urine ketones are produced when the body is burning fat rather than glucose as its primary fuel source — a process called ketosis. When fat is metabolised, the liver produces ketone bodies (acetoacetate, beta-hydroxybutyrate, and acetone), which are used for energy. When ketone production exceeds utilisation, they are excreted in urine.
Ketones in urine can be normal in the context of fasting, low-carbohydrate diets, or intense exercise. However, high levels of ketones — particularly in a person with diabetes — may indicate diabetic ketoacidosis (DKA), a life-threatening emergency where the body is severely insulin-deficient. Urine ketone testing is a rapid and important screening tool for DKA in people with type 1 diabetes who are unwell.
FAQs
Is urine ketone testing reliable for DKA?
Urine ketones detect acetoacetate but not beta-hydroxybutyrate, the predominant ketone in DKA. Blood ketone meters measuring beta-hydroxybutyrate are more accurate and preferred for DKA monitoring. Urine testing is a useful screening tool.
Is having ketones in urine bad if I am on a ketogenic diet?
No. Urine ketones during a ketogenic diet indicate successful fat metabolism (ketosis), which is the intended metabolic state. This is distinct from ketoacidosis.
What should a person with type 1 diabetes do if urine ketones are positive?
Test blood glucose, take corrective insulin, drink water, and contact a diabetes care team if ketones are moderate to large (++ or more) or blood glucose is not responding to treatment. DKA requires urgent medical attention.
Can urine ketone sticks expire?
Yes. Expired strips may give false-negative results. Always check the expiry date and store strips in a sealed container away from heat and moisture.
