Ketones in Urine · high result
Ketones in urine: what they mean, causes and when they are an emergency
Short answer
Ketones in urine mean the body is burning fat for fuel. After an overnight fast, on a ketogenic diet, after a long workout, in early pregnancy or during a vomiting illness, small ketones are expected and harmless. In someone with diabetes, moderate or large ketones — especially with a glucose above 250 mg/dL, nausea, vomiting, abdominal pain or rapid breathing — mean diabetic ketoacidosis until a blood ketone and metabolic panel prove otherwise.
Medically reviewed by Youmna DiStefano, MD · Last reviewed November 2026
When does this result need same-day care?
- Moderate or large ketones with a blood glucose above 250 mg/dL, or any ketones with vomiting, abdominal pain, rapid breathing, drowsiness or confusion — emergency care
- Any ketones in an unwell person taking an SGLT2 inhibitor, regardless of glucose — emergency care
- Ketones with heavy recent drinking and vomiting, or in a pregnant woman who cannot keep fluids down — same-day assessment
What is the normal range for Ketones in Urine?
Ketones (mainly acetoacetate) on the urine dipstick, the by-product of burning fat for fuel. Normally negative; graded trace (5 mg/dL) to large (80–160 mg/dL).
Fasting, a ketogenic or very-low-carbohydrate diet, prolonged exercise, vomiting and pregnancy produce small to moderate ketones; large ketones with a high blood glucose, thirst, nausea or rapid breathing is diabetic ketoacidosis, an emergency.
Full reference table, citations and testing options: Ketones in Urine biomarker page.
What are the common causes of high Ketones in Urine?
- Fasting for more than 12–18 hours, skipped meals, crash dieting and eating disorders
- A ketogenic or very-low-carbohydrate diet — ketones are the intended result
- Prolonged or intense exercise, especially fasted
- Pregnancy — fasting ketosis develops faster, and hyperemesis produces moderate to large ketones from starvation and dehydration
- Vomiting, diarrhea or any illness with poor intake; in children, almost any febrile illness
- Heavy alcohol use — alcoholic ketoacidosis after a binge with vomiting and little food
- Diabetic ketoacidosis — insulin deficiency in type 1 diabetes (missed doses, pump failure, new diagnosis), severe illness or infection in type 2 diabetes
- Euglycemic ketoacidosis on SGLT2 inhibitors (empagliflozin, dapagliflozin, canagliflozin, ertugliflozin) — the glucose can be near normal
- False positives — captopril, mesna, N-acetylcysteine, levodopa, valproate metabolites and strongly pigmented urine; isopropyl alcohol ingestion produces true acetone
What symptoms go with high Ketones in Urine?
- None with fasting, dietary or exercise ketones beyond a fruity or acetone smell on the breath
- Thirst, frequent urination, dry mouth and fatigue as ketones rise with high glucose
- Nausea, vomiting, abdominal pain and loss of appetite
- Deep, rapid breathing, drowsiness and confusion in ketoacidosis
What do clinicians usually check next?
- Check a blood glucose; with diabetes, a blood ketone (beta-hydroxybutyrate) — the urine strip misses the dominant early ketone and lags in both directions
- A basic metabolic panel for bicarbonate and the anion gap when ketones are moderate or large or any symptoms are present; ketoacidosis is bicarbonate below 18 mmol/L with a raised gap
- Follow your sick-day plan if you have diabetes — extra rapid-acting insulin and fluids as instructed, never stopping basal insulin — and seek care if ketones do not fall
- Without diabetes: eat a carbohydrate-containing meal, hydrate and repeat; fasting, diet and exercise ketones clear within hours
- In pregnancy: food and fluids, then assessment for hyperemesis and intravenous fluids if ketones persist or fluids cannot be kept down
- Persistent ketones in someone eating normally: glucose, hemoglobin A1c, a metabolic panel and a review of medications and alcohol
Follow-up tests available at TestWell: Basic Metabolic Panel ($17.99), Hemoglobin A1c Test ($18.99), Glucose Test ($14.99).
How do you recheck Ketones in Urine?
Prices are cash-pay; every order adds one $6 lab processing fee. Physician authorization is included; no insurance or referral needed.
| Test or panel | Type | Price | Fasting | Results |
|---|---|---|---|---|
| Kidney Health Panel | Panel · 4 tests | $64.99 | Yes | 2–4 business days |
| Early Pregnancy Panel | Panel · 9 tests | $249.99 | No | 3–5 business days |
| Men's Total Body Advanced Panel | Panel · 65 tests | $999.99 | Yes | 5–10 business days |
| Complete Urinalysis Test | Test · 14 biomarkers | $17.99 | No | 1–3 business days |
Common questions
What causes ketones in urine?
Burning fat for fuel: fasting, a ketogenic or low-carbohydrate diet, long exercise, pregnancy, a vomiting illness and heavy drinking all produce them in people without diabetes, usually at trace to small levels that clear with a meal. In diabetes, ketones mean insulin is insufficient, and moderate or large ketones with a high glucose or any feeling of illness are treated as ketoacidosis until proven otherwise.
Are ketones in urine during pregnancy dangerous?
Small morning ketones are common in pregnancy because fasting ketosis develops faster, and they respond to eating. Persistent moderate or large ketones — typically with severe nausea and vomiting — signal starvation and dehydration (hyperemesis) and need assessment and fluids. In a pregnant woman with diabetes, ketones are managed as a possible ketoacidosis and are urgent.
What level of ketones in urine is dangerous?
Moderate (about 40 mg/dL) or large (80–160 mg/dL) ketones in someone with diabetes, particularly with a glucose above 250 mg/dL or symptoms of nausea, vomiting, abdominal pain or rapid breathing, is the danger level and needs emergency care. Without diabetes the same readings after a long fast or a stomach bug are far less likely to mean acidosis, but should still be explained and rechecked after eating.
Why are urine ketones still positive when I feel better?
The dipstick detects acetoacetate, and as ketoacidosis resolves the body converts beta-hydroxybutyrate back into acetoacetate, so urine ketones can rise or linger for a day after the blood has cleared. Urine ketones are also a record of the hours since the bladder last emptied. Blood ketone levels are the better guide to recovery.
Educational content, not a diagnosis. Lab results are one input; a clinician interprets them with your history and exam.