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Blood Test Tracker

Urine Ketones (Dipstick)

A dipstick check for ketones, which your body makes when it burns fat for energy. Fasting, low-carb eating and illness can all raise it.

AI-verified against cited sources. Awaiting expert reviewAlso called KETLOINC 2514-8

What it is

Ketones are chemicals your liver makes when your body burns fat instead of sugar for energy. Some of them pass into your urine. The dipstick mostly detects one ketone, acetoacetate. Most people who are eating normally have little or none in their urine. Results are reported as negative, trace, small, moderate or large (or 1+ to 4+), and some analyzers print a number in mg/dL or mmol/L.

Why it matters

Ketones in urine are common and often harmless after a long gap between meals, on a low-carb diet, after hard exercise, in pregnancy, or when you have been vomiting. In people with diabetes, a lot of ketones together with high blood sugar can be an early warning of diabetic ketoacidosis, which is a medical emergency. That is why people with diabetes may be asked to check ketones when they are sick. The urine strip is a quick first check. A blood ketone test (beta-hydroxybutyrate) is more specific when it matters.

If it’s high

Ketones in your urine mean your body is using more fat for fuel than usual. That has many everyday explanations. Larger amounts, especially with high blood sugar in a person with diabetes, deserve prompt attention.

Common causes

  • Going a long time without eating, including fasting or skipped meals
  • Low-carbohydrate or ketogenic eating
  • Hard or long exercise
  • Pregnancy
  • Vomiting or diarrhea that lasts a long time
  • Long-term heavy drinking (alcohol use disorder)
  • Eating disorders or starvation
  • Diabetes that isn't well controlled, including diabetic ketoacidosis, which is more common in type 1 diabetes
  • SGLT2 inhibitor medicines, which can raise the chance of ketoacidosis in people with diabetes, sometimes even when blood sugar is not very high

What can help

  • If you have diabetes, follow the ketone-testing and sick-day plan your care team gave you
  • Ask your clinician whether a blood ketone (beta-hydroxybutyrate) test makes sense for you
  • If you eat low-carb on purpose, ask your clinician how best to track ketones
  • Keep up fluids and regular meals when you can, unless your clinician has told you otherwise

What can affect your result

  • Fasting, skipped meals and low-carbohydrate diets raise urine ketones
  • Time on a low-carb diet: urine ketones can fall back over weeks as the body adapts, even if blood ketones stay raised
  • Hard exercise, pregnancy, vomiting and alcohol
  • SGLT2 inhibitors, which raise the chance of ketoacidosis in people with diabetes
  • Hydration: concentrated urine can read higher and dilute urine lower
  • How long the sample sat before testing: delays of more than about two hours can make results unreliable
  • Some medicines can cause false-positive readings
  • The strip mainly detects acetoacetate, so it is not the same measurement as a blood ketone meter
  • The strip detects acetoacetate (not beta-hydroxybutyrate), so it can under-read early in ketoacidosis and over-read later in recovery.
  • A sample left for more than about two hours before testing can give unreliable results, so it should be tested promptly or refrigerated.
  • Some medicines can cause false positives, including captopril and other sulfhydryl drugs, valproate, mesna and levodopa metabolites; phenolphthalein, very acidic urine and very concentrated urine can too.
  • As the body adapts to long-term low-carbohydrate eating, the kidneys reabsorb more acetoacetate and urine strips can read lower even when blood ketones stay raised.
  • Hydration changes how concentrated the urine is, which affects the reading.
  • Strongly colored urine, such as from phenazopyridine, can interfere with the color pads.

Any time. Some clinicians ask for a fast beforehand for specific reasons, so follow the instructions you were given. A midstream clean-catch sample is preferred, and the sample should be tested promptly. Shows ketones that passed into urine since your bladder was last emptied, so it reflects the last few hours.

When to talk to a clinician

If you have diabetes or take an SGLT2 inhibitor and your urine ketones are moderate or large (2+ or more), contact the clinician who ordered the test or your care team the same day. Get urgent medical help if you also have nausea or vomiting, belly pain, confusion, trouble breathing, feeling very tired or sleepy, or fruity-smelling breath. Call 911 or your local emergency number if you feel very unwell.

Questions you could ask

  • Is a urine strip or a blood ketone meter the better choice for my situation?
  • Should I check blood ketones as well as urine ketones?
  • Could my diet, fasting or a recent illness explain this result?
  • If I have diabetes, when should I check ketones, and who should I call if they are high?

Questions people ask

Does a positive ketone result mean I'm in ketosis from my diet?

Often, but not always. Low-carb eating, fasting and many other things raise urine ketones. As your body adapts to a low-carb diet, urine strips can show less even if you are still in ketosis, so they get less reliable over time. Blood ketone meters measure beta-hydroxybutyrate and are more precise.

Are ketones in my urine a problem?

Usually not. Small amounts are common after fasting, hard exercise, a low-carb day or a stomach bug. They matter more if you have diabetes, because large amounts with high blood sugar can signal diabetic ketoacidosis, which needs urgent care. See the section on when to seek care.

Why does my urine strip show ketones when my blood test doesn't, or the other way around?

Strips mainly detect acetoacetate, while blood meters measure beta-hydroxybutyrate. The two don't always move together, and timing and hydration shift urine results. In ketoacidosis, strips can read low early on and stay positive after blood ketones have started to fall.

Can I have ketones with normal blood sugar?

Yes. Fasting, low-carb eating, pregnancy and vomiting can all do it. In people who take SGLT2 inhibitors, ketoacidosis can also happen when blood sugar isn't very high, so ketone checks matter if you feel unwell. If you take one, ask your clinician what to do.

Show the science and sources

Units

  • 1 mg/dL = 1 mg/dL
  • 1 mg/dL = 0.09795 mmol/L

For clinicians and researchers

The pad uses the nitroprusside (nitroferricyanide) reaction with glycine, which detects acetoacetate but not beta-hydroxybutyrate, the main ketoacid in diabetic ketoacidosis. The 2024 ADA, EASD, JBDS, AACE and DTS consensus report notes that urine and blood ketones have similar diagnostic sensitivity but blood beta-hydroxybutyrate is more specific; urine testing can underestimate severity early in DKA because of a lag in acetoacetate formation and overestimate it later as beta-hydroxybutyrate converts to acetoacetate, so it recommends blood beta-hydroxybutyrate for diagnosis and monitoring and says urine ketones should not be used to judge DKA resolution. A blood beta-hydroxybutyrate of 3.0 mmol/L or more correlates well with acid-base changes. Sulfhydryl drugs such as captopril and valproate can give false-positive nitroprusside results. Nutritional ketosis is defined by blood beta-hydroxybutyrate of 0.5 to 5.0 mmol/L, and as ketosis is sustained, renal reabsorption of acetoacetate rises and urine strips become less reliable (Fante 2025). SGLT2 inhibitor labeling advises assessing for ketoacidosis regardless of blood glucose and considering ketone monitoring in people at risk. On the Siemens Multistix strip read in one 2019 study, steps corresponded to trace 5, + 15, ++ 40, +++ 80 and ++++ 160 mg/dL; other brands differ and some print mmol/L (the catalog's mmol/L factor uses acetoacetic acid, 102.09 g/mol, and printed mmol/L steps are rounded). Quest lists 'Negative' as the expected result for Urinalysis, Complete (5463).

LOINC 2514-8 (primary), 5797-6, 57734-6, 50557-8, 22702-5, 59158-6. Specimen: urine.

Sources

  1. Ketones in Urine (MedlinePlus Medical Test), MedlinePlus, U.S. National Library of Medicine
  2. Urinalysis (MedlinePlus Medical Encyclopedia), MedlinePlus, U.S. National Library of Medicine (2025)
  3. Urinalysis: A Comprehensive Review, American Family Physician (2005)
  4. Hyperglycemic Crises in Adults With Diabetes: A Consensus Report, Diabetes Care (ADA, EASD, JBDS, AACE and DTS consensus report) (2024)
  5. JARDIANCE (empagliflozin) tablets, prescribing information, Boehringer Ingelheim, via DailyMed (U.S. National Library of Medicine) (2026)
  6. The role of β-hydroxybutyrate testing in ketogenic metabolic therapies, Frontiers in Nutrition (2025)
  7. Urinalysis, Complete (test code 5463), Quest Diagnostics
  8. Urinalysis, Complete With Microscopic Examination (test 003772), Labcorp
  9. Evaluation of the Clinitek, a point-of-care urinalysis system for the measurement of clinically significant urinary metabolites and detection of haematuria in Schistosoma haematobium infected children in southern Côte d'Ivoire, Parasites & Vectors (2019)
  10. Acetoacetic acid (PubChem compound 96), PubChem, U.S. National Library of Medicine

AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.

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