What Causes Ketones in the Urine? (& Symptoms of Ketonuria)

Clinical review: Marcela Lemos
Biomedical Scientist
March 2023

High ketone levels in the urine are usually a sign of increased fat breakdown in the body. When carbohydrates are no longer available for energy, the body resorts to breaking down fat instead. Ketones, therefore, are a by-product of fat metabolism. This condition is also referred to as ketonuria. 

Urine ketone levels can rise as a result of extended periods of fasting, very strict diets or diabetic ketoacidosis. A ketogenic diet for example, promotes increased fat burning in the body, and can lead to ketones in the urine. 

Doctors usually prescribe ketone urine tests to people with type 1 diabetes with the purpose of checking their body's response to treatment. This means that, in people with diabetes, high ketone levels can indicate that the insulin treatment is not being done correctly or that it needs to be readjusted.

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Common Causes

High ketone levels in the urine may be a result of several conditions, such as:

  1. Decompensated diabetes
  2. Diabetic ketoacidosis
  3. Extended fasting
  4. Pancreatic problems
  5. Excessive exercise
  6. Diets low in carbohydrates and rich in fat, like a keto diet
  7. Pregnancy
  8. Fevers, especially from infections
  9. Frequent vomiting

Having high levels of ketones in urine is not always a sign of a health condition, since it can be caused by simple lifestyle changes, such as restrictive diets or exercise.

Nonetheless, having high ketone levels, especially if accompanied by symptoms such as nausea, fatigue or confusion, may indicate some type of health problem that needs proper treatment in order to avoid serious complications. Therefore, it is always recommended for the test results to be evaluated by a physician.

Lab testing

The level of ketones in urine can be measured through a conventional urine test strip, in which it is possible to observe a change in color on the test band representing the ketone parameter.

However, it's important that these values be confirmed through another urine test or blood test, as the person's hydration level can interfere with the result of the urine test strip, providing a false-positive result, when the person is dehydrated, or a false-negative result, when the person has drank a lot of water.

Common symptoms

When there are high ketone levels in the urine, it is also common to find blood in the urine sample. Other than that, high ketone levels can also be identified through some symptoms like excessive thirst, frequent need to urinate, fatigue, metallic taste inn the mouth, or nausea. 

The main symptoms that can indicate ketones in the urine include: 

  • Excessive thirst
  • Increased urinary frequency
  • Foul breath with metallic taste
  • Fatigue
  • Red skin
  • Abdominal pain
  • Nausea 

Normally, when ketones are found in the urine, they will also be present in the blood. This is known as a state of ketosis. 

What you should do

High levels of ketones in urine should always be investigated by a doctor, and treated if needed. This is because an accumulation of ketones in the blood can result in several health problems such as dehydration, electrolytic unbalance, acidosis, and even coma.  

From the moment ketonuria is identified, doctors may prescribe the use of insulin, fluid replacement through IV, or some dietary changes in order to achieve ideal amounts of carbohydrates, proteins, and fat in the diet.  

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Written and updated by Daisy Oliveira - Registered Nurse on March of 2023. Clinical review by Marcela Lemos - Biomedical Scientist, on March of 2023.


  • Campuzano Maya Germán(1), Arbeláez Gómez Mario(2) Médico especialista en Hematología y Patología Clínica.(1) Profesor ad honoren, Facultad de Medicina, Universidad de Antioquia. Director Laboratorio Clínico Hematológico. Médico especialista en Medicina Interna y Nefrología. Profesor Titular. Jefe, Sección de Nefrología.(2) Departamento de Medicina Interna, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombi. El Uroanálisis: Un gran aliado del médico. Revista Urología Colombiana. 2007
Clinical review:
Marcela Lemos
Biomedical Scientist
Masters in Applied Microbiology, and skilled in clinical analysis. Bachelor‘s in Biomedicine and licensed to practice through CRBM /PE license #08598.