Ketones in urinalysis: understanding the finding

The body makes ketones when it has less available glucose or cannot use glucose effectively. Fasting, reduced food intake, vomiting, dehydration and a low-carbohydrate eating pattern can contribute. In diabetes, ketones can indicate that insulin is not meeting the body's needs and may precede ketoacidosis. Urinalysis is only one part of the picture: glucose, blood ketones, hydration, breathing and general appearance help clinicians judge urgency.

Check how the laboratory or strip described the result and note whether you were fasting, unwell or following a restricted diet. If you have diabetes, follow your sick-day instructions for glucose and ketone checks, fluids and contacting your care team. Do not assume that treating a urine result with antibiotics is appropriate; ketones are not a sign of a urinary infection by themselves. A clinician may repeat the urine test or arrange blood tests.

Seek urgent care if ketones occur with repeated vomiting, severe stomach pain, unusual thirst, deep or rapid breathing, fruity-smelling breath, confusion or extreme drowsiness. This is especially important for anyone with diabetes or who cannot keep fluids down. Fever, painful urination or flank pain points to a separate urinary problem that also deserves medical assessment.

Ask what the result means alongside your glucose reading, whether blood ketones are needed, how to handle future illness and which symptoms require emergency help. Mention every medicine, supplement and diet change so the interpretation is accurate.