Ketones in Urine

What are ketones in urine?

Ketones are acids your body makes when it has to use body fat for energy instead of glucose (sugar). As your body breaks down fat, it makes ketones — they’re byproducts of this process. Like other chemical byproducts your body makes, ketones eventually leave your body through your urine (pee). But they can be in your blood, as well. Having ketones in your urine is called ketonuria.

Having some, or trace, ketones in your urine is normal. There may be times when your body needs to use fat as its backup source of energy. This may happen when you’re sleeping, fasting or eating a low-carbohydrate diet (keto diet).

In high amounts, ketones are toxic to your body — they make your blood too acidic. This is called ketoacidosis. It mainly affects people with diabetes and is better known as diabetes-related ketoacidosis (DKA). People with ketoacidosis have high levels of ketones in their blood and usually have high levels in their urine. Ketoacidosis is life-threatening and requires immediate medical care.

Measuring ketones in urine

There are two ways to measure ketones in urine:

• At-home tests: You can buy over-the-counter (OTC) ketone urine test kits at a pharmacy or online. They’re usually test strips that you dip into your pee. You pee into a container, dip the stick into the pee and wait for it to change color. You then compare the strip’s color to a chart that came with the strips, showing a color range for different levels. The color ranges usually refer to the amount of ketones as “negative,” “trace,” “small,” “moderate” or “large.” People with diabetes and those on a keto diet most often use these strips.
• Medical tests: Healthcare providers can measure urine ketone levels with a urinalysis. If you have signs of ketoacidosis, they’ll likely order a blood ketone test. This test is more accurate and shows the levels of ketones currently in your body. Blood tests usually give exact numbers of ketone levels instead of ranges.

It takes time for your body to produce enough pee for you to go to the bathroom. So, urine tests can’t show your body’s current ketone levels. But they can tell you what your ketone levels were within the last few hours.

What causes ketones in urine?

Your body much prefers to use glucose as its main energy source to fuel all your cells. Glucose comes from the carbohydrates (carbs) you consume. But certain situations “force” your body to break down fat (and sometimes muscle) for energy instead.

Your body will switch to ketosis if you’re not getting enough carbs, or if you don’t have enough insulin to help your body use glucose. During ketosis, your body breaks down fat for energy, releasing ketones. They eventually leave your body through your urine (pee).

Common activities like sleeping and fasting can lead your body to ketosis, which can produce very small amounts (trace amounts) of ketones in your urine. This is normal and healthy.

Eating a ketogenic (keto) diet also leads to ketosis. The keto diet is high in fat, adequate in protein and very low in carbs. A typical keto diet consists of 70% to 80% fats, 20% proteins and 5% to 10% carbs. People who eat a strict keto diet typically have ketones in their urine.

Abnormal levels of ketones (small, moderate or high levels) in your urine can happen due to:

• Diabetes: Everyone needs insulin (a hormone) to be able to use glucose as an energy source and to live. If you have diabetes, your body either doesn’t make any or enough insulin, or it doesn’t use insulin properly. This causes glucose to build up in your blood, leading to high blood sugar. In addition, without insulin, your body can only use fat for energy. If you continue to have a lack of insulin, more and more ketones build up. This can lead to diabetes-related ketoacidosis (DKA), which is life-threatening.
• Alcohol use disorder: Long-term excessive alcohol consumption can affect how your body absorbs nutrients (like carbs) and how it stores glucose (as glycogen) in your liver. This can force your body to break down fat and can lead to alcohol-related ketoacidosis. Like DKA, it’s life-threatening.
• Pregnancy: Gestational diabetes is the most common cause of ketones in urine during pregnancy. But all the other causes in this list can produce ketones during pregnancy, as well.
• Prolonged vomiting and/or diarrhea: if you vomit or have diarrhea for a long time, your body may run out of glucose for energy, leading to ketones in your urine.
• Eating disorders and starvation: Certain eating disorders (like anorexia) and starvation can limit the amount of carbs and glucose in your body. This can lead to ketones in your urine.
• Prolonged, intense exercise: If you use up all of your body’s stored glucose (glycogen) for energy during intense and prolonged exercise, your body starts breaking down fat for energy. This can lead to ketones in your urine.

Can you have ketones in your urine if you don’t have diabetes?

Yes, you can have trace or small levels of ketones in your urine even if you don’t have diabetes. But it’s abnormal to have moderate or large amounts of ketones in your urine if you don’t have diabetes. Call 911 (or your local emergency service number) or go to the nearest emergency room if this happens. You may have undiagnosed diabetes or another serious condition.

What is a normal ketone level in urine?

For most people, it’s normal and safe to have “trace” or “small” levels of ketones in your urine.

If you have diabetes or another condition that puts you at risk for ketoacidosis, this level can be a warning sign, depending on the situation. If you have high blood sugar (over 250 mg/dL), you should carefully monitor your blood sugar and continue to check your urine for ketones to make sure the ketone level doesn’t increase.

What is a dangerous level of ketones in urine for a person with diabetes?

Any level of ketones over “small” or “trace” amounts is potentially dangerous, especially if you’re at risk of ketoacidosis.

A small amount of ketones in your urine increases your risk of ketoacidosis. If you have diabetes, contact your diabetes healthcare provider for advice on how to manage this.

A moderate or large amount of ketones puts you at serious risk of ketoacidosis. Go to the nearest hospital for medical treatment.

What does trace ketones in urine mean?

A “trace” level of ketones in your urine is typically a safe and healthy level for people who don’t have diabetes. Most people have trace levels of ketones in their urine at any given time.

Can ketones in urine cause symptoms?

Yes, if you have ketones in your urine, you may have other symptoms, depending on the amount.

Ketosis symptoms

Ketosis, which usually leads to small amounts of ketones in your urine, can cause the following symptoms:

• Upset stomach.
• Headache.
• Fatigue.
• Brain fog.
• Bad breath (“keto” breath).
• Constipation.
• Insomnia.

Ketoacidosis symptoms

Moderate to high amounts of ketones in your urine can mean you have ketoacidosis — either DKA or alcohol-related ketoacidosis.

Early symptoms of DKA include:

• Peeing more often than usual (frequent urination).
• Extreme thirst (polydipsia).
• Extreme hunger (polyphagia).
• Dehydration.
• Headache.

More severe symptoms of DKA and symptoms of alcohol-related ketoacidosis can include:

• Nausea and vomiting.
• Abdominal pain.
• Diarrhea.
• Shortness of breath or Kussmaul breathing.
• Fruity-smelling breath.
• Feeling very tired or weak.
• Feeling disoriented, agitated or confused (altered mental status).
• Decreased alertness.

Get immediate medical help if you have these symptoms.

A note from Cleveland Clinic

In small amounts, ketones are harmless. But large amounts can become life-threatening. If you’re at risk of ketoacidosis, talk to your healthcare provider about how to manage it. Also, talk about what steps to take if your ketones get too high. Having a plan in place can keep you safe.