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Ketones in Urine (Urine Ketones): What Your Result Means

What the urine ketone pad measures, what negative, trace, small, moderate, and large results mean, the common causes from fasting and keto diets to diabetic ketoacidosis, and when to get care.

Published

August 10, 2024

Last updated

October 28, 2026

Read time

4 min read

Medically reviewed by

Rhonda Collins, FNP-C

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Ketones in urine mean your body has been breaking down fat for energy because it could not get enough glucose. That happens with fasting, a very low carbohydrate (keto) diet, long bouts of vomiting, and hard prolonged exercise. In someone with diabetes, ketones can also be an early sign of diabetic ketoacidosis (DKA), a medical emergency ^[1].

What does a urine ketone test measure?

The urine ketone test is one pad on the routine urinalysis dipstick. The pad changes color when it reacts with ketones, the acids the liver makes from fat ^[2][3]. The liver makes mainly two ketone bodies, acetoacetate and beta-hydroxybutyrate. They are released into the blood, and when production outpaces use, they spill into the urine ^[2]. Depending on the brand of test strip, some ketones may not be detected ^[4].

On a Mito report this result appears as urine ketones, next to the other dipstick results such as urine glucose and urine protein.

What do negative, trace, small, moderate, and large urine ketones mean?

Urine ketones are reported as negative, as trace, or as a positive amount. Positive amounts are usually listed as small, moderate, or large, and some reports give a number instead ^[1][5].

• Negative: the expected result. MedlinePlus describes a negative test as normal ^[5].
• Trace: a very faint reaction. Cleveland Clinic lists negative, none, or trace as the normal finding for ketones on a urinalysis ^[6].
• Small, moderate, or large: ketones are present, and a larger amount means a stronger reaction. MedlinePlus notes that normal results vary with diet, activity, and other factors, so the meaning depends on why your body is making ketones ^[1].

The grade alone does not tell you the cause. Read it with what you ate, how active you were, and whether you have diabetes or symptoms, because those decide what the same amount means ^[1].

What causes ketones in urine?

Ketones appear in urine whenever the body shifts from glucose to fat for fuel ^[1][2]. Common causes include:

• Fasting, skipped meals, or starvation, including eating disorders ^[1][5].
• A ketogenic or other very low carbohydrate diet. Ketones are an expected result of this way of eating ^[1][5].
• Long-lasting vomiting or diarrhea, including vomiting in early pregnancy ^[1][5].
• Pregnancy ^[1][4].
• Hard exercise over a long time ^[1].
• Acute illness, high fever, or hyperthyroidism ^[5].
• Alcohol use disorder, which can cause alcoholic ketoacidosis ^[1].
• Uncontrolled diabetes, the condition most commonly associated with ketones in urine ^[3]. Diabetic ketoacidosis is most common in type 1 diabetes but can also happen in type 2 ^[1].
• SGLT-2 inhibitor medicines for diabetes, which can cause severe ketosis even without high blood sugar in people with diabetes ^[5].

Can a urine ketone result be wrong?

Yes. Some drugs, including mesna and certain levodopa metabolites, can cause a falsely positive ketone reading. A sample left too long before testing can read falsely negative ^[3].

Are ketones in urine dangerous?

Having some ketones in urine is normal, and ketones from fasting or a keto diet are an expected result ^[1]. Ketones become dangerous when they build up faster than the body can clear them and make the blood too acidic, a condition called ketoacidosis ^[1][2]. The most common form is diabetic ketoacidosis, in which a lack of insulin lets fat breakdown run unchecked. It often develops quickly and can be life threatening ^[1][2].

Early symptoms of ketoacidosis include urinating a lot, extreme thirst or hunger, dehydration, and headache. Severe symptoms include nausea or vomiting, belly pain, confusion, trouble breathing, unusual tiredness, and fruity-smelling breath ^[1].

When should I talk with a clinician about urine ketones?

If you have diabetes and your urine shows ketones, or you have any of the severe symptoms above, seek medical help right away: large amounts of ketones can be life threatening ^[1]. If you do not have diabetes and the result is unexpected, for example you were not fasting or following a low carbohydrate diet, review it with your clinician alongside your urine glucose and blood sugar results.

Urine ketone testing with Mito

The Urinalysis, Routine Test includes the urine ketone pad along with glucose, protein, nitrite, and the other dipstick and microscopy results. Check the product page for current pricing and availability.

Related Urine Ketones Resources

• How to Improve Your Urine Ketones Level Naturally

References

1. MedlinePlus: Ketones in Urine
2. Rahimi N, Gupta S. Biochemistry, Ketogenesis. StatPearls. 2025
3. Simerville JA, Maxted WC, Pahira JJ. Urinalysis: A Comprehensive Review. Am Fam Physician. 2005
4. Hitzeman N, Greer D, Carpio E. Office-Based Urinalysis: A Comprehensive Review. Am Fam Physician. 2022
5. MedlinePlus Medical Encyclopedia: Ketones urine test
6. Cleveland Clinic: Urinalysis