Urine Ketone Test: Purpose, How to Buy, Strip Results

Instructions for At-Home Ketone Kits

A urine ketone test is an alternative to blood ketone testing for monitoring levels of ketones—a type of fuel that results when the liver breaks down fat for energy. For people who have diabetes, the production of ketones can speed up when the body is lacking effective insulin to use glucose as fuel and instead breaks down fat, leading to a build-up of these organic compounds in the blood and urine called diabetic ketoacidosis (DKA).

DKA is dangerous and can lead to coma or even death if not treated right away. That's why it's important for people with diabetes to understand how to test themselves for ketones, including how to select and use ketone test strips, and how to interpret the results.

This article will go over how to do a urine ketone test at home. You will also learn how to choose ketone test strips and what your urine ketone test results mean.

What Causes DKA?

Diabetic ketoacidosis (DKA) is a serious complication of diabetes. One sign of DKA is high levels of ketones in your urine.

If you have diabetes, there are three circumstances in which you might develop a large number of ketones:

  • Insufficient insulin: This could occur if you administer too little supplemental insulin or if you have an illness that increases the amount of insulin your body needs.
  • Not eating enough food: Skipping meals or eating too little due to a lack of appetite could put you at risk of DKA.
  • Insulin glucose (low blood sugar): You may have had an insulin reaction while asleep, which can cause high levels of ketones in the morning

Who Should Test for Ketones?

DKA is more likely to develop in someone who has type 1 diabetes, but a person with type 2 diabetes can be at risk if they have uncontrolled blood sugar, are missing doses of medication, or have a severe illness or infection.

According to the American Diabetes Association (ADA), there are a number of conditions under which people with diabetes should test themselves for ketones (in addition to any specific instructions given by a healthcare provider or healthcare provider):

  • When blood glucose is more than 240 mg/dl
  • In response to symptoms such as nausea, vomiting, and abdominal pain
  • During periods of illness such as a cold or flu
  • When experiencing constant fatigue
  • In response to extreme thirst or a very dry mouth
  • When skin appears flushed
  • When breathing is difficult
  • When breath smells fruity
  • In response to feeling confused or "in a fog"

Accuracy of Ketone Test Strips

Testing your urine for ketones yourself is generally considered less accurate than a blood ketone test. However, when done it's correctly, testing your urine for ketones at home can help you monitor a condition or know when it's time to call your provider for more care.

Reasons to Test Ketones If You Don't Have Diabetes

Diabetes might be the most common reason to check your ketone levels, but there are other conditions or reasons why you might want to do a urine ketone test.

Usually, your body uses glucose for energy. There are some conditions or circumstances in which your body will start breaking down fat for energy instead. When this happens, you might have more ketones in your urine.

Health conditions or lifestyle changes that can cause ketones in your urine include:

  • Pregnancy and/or breastfeeding
  • Prolonged vomiting and diarrhea (e.g., illnesses, morning sickness, eating disorders)
  • Not eating for an extended time (e.g., fasting, eating disorders)
  • Alcohol use
  • Serious illnesses, infections, or injuries (e.g., burns, sepsis)
  • High fevers
  • Having too much thyroid hormone (hyperthyroidism)
  • Not eating many (or any) carbohydrates

Urine Ketone Tests for Keto Diet and Ketosis

People who are on a low-carb or no-carb diet—specifically, a ketogenic or "keto" diet—sometimes test their urine for ketones at home to see if their body has started using fat for energy (a state called ketosis).

Using a home urine ketone test to check for ketosis is the same as using it to check your urine for ketones if you have diabetes.

The main difference is that once you've been doing a keto diet for a while, your body will adjust. If you test your urine often, you'll probably notice only "trace" amounts of ketones. That doesn't mean you're not in ketosis, it just means your body has adapted to the changes you've made in your diet.

How to Choose Ketone Test Strips

There are many brands of urine ketone test strips available over the counter (OTC) at drugstores, supermarket pharmacies, and other stores where medical supplies are sold. Ketostix is a common brand. Ketone urine test strips are also available by prescription.

The best way to select urine ketone test strips is to ask your provider for recommendations or a prescription. The U.S. Food and Drug Administration (FDA) issued a warning in 2019 not to purchase or use pre-owned test strips sold at a discount on online marketplaces like Amazon, eBay, or Craigslist.

The FDA also warns against buying or using ketone test strips that aren't authorized to be sold in the United States (one clue: the instructions are in a language other than English).

According to the FDA, substandard urine ketone test strips could provide inaccurate results: "If a user receives an inaccurate result from a test strip and uses this result as a basis for their treatment, they could take too much medication or not enough medication potentially leading to serious patient injury, including death."

How to Use Ketone Testing Strips

Whatever brand of ketone test strips you buy, it's important to read the product insert in detail to see if the directions for use vary from the generic ones below. If they do, follow those exact instructions for doing the urine ketone test instead.

ketone testing strips
Verywell Health / JR Bee

Saturating the Test Strip

To do a urine ketone test, you need to get your urine onto the test strip.

There are two ways to saturate a ketone test strip with urine. One is to simply hold the test strip in the stream of your urine until it's saturated.

The other is to collect a "clean-catch" sample. To do this, wash your hands and clean your genital area: If you're a man, wipe the tip of your penis with a disposable cleaning cloth. If you're a woman, open your labia and use the cloth to clean from front to back.

As you urinate into the toilet, hold the collection cup in the urine stream until you've got an ounce or two. The cup likely will have markings to indicate the amount. After you've finished peeing and have washed your hands, dip a test strip into the cup to saturate it thoroughly.

Interpreting the Results

If the ketone test strip takes on any color other than the original beige, it's an indication that there are some ketones in your urine. Compare the color of the test strip to the color chart that comes with the test kit; this will give you a range of how many ketones are in your urine.

When you look at the results of the urine ketone test, if it appears that you have small or trace amounts of ketones in your blood, it may indicate the beginning of ketone buildup. In that case, the ADA recommends testing your urine for ketones again in a few hours.

If your urine ketone test results show you have moderate or large amounts of ketones in your urine, take this as a danger sign. Call your healthcare provider right away.

The ADA also advises keeping a log of your urine ketone test results that you can share with your healthcare provider. They can use this information to help make changes to your diabetes management plan if necessary.

Tips for Accuracy

Testing urine for ketones is not as accurate as testing blood. The results of a urine ketone test can vary depending on how diluted your urine is, for example. However, if it's your preferred way to test for ketones, there are steps you can take to get results that are as reliable as possible.

  1. Always check the expiration date on the testing kit. An expired kit can give false results.
  2. Store test strips with the lid tightly closed. Moisture or long exposure to air will cause the strips to work improperly.
  3. When it comes to when to test your urine for ketones, the early morning or after dinner are best. Research has found that results are most reliable at these times.
  4. If you have trouble distinguishing colors, ask a friend or family member to help you interpret your test results.

Summary

A urine ketone test looks for compounds called ketones in your urine. You can use urine ketone test strips to test your urine at home. If you have diabetes, you may need to do a urine ketone test regularly.

There are also other conditions or lifestyle factors that cause ketones in your urine, like following a no-carb diet, fasting, or having an infection that causes vomiting and diarrhea.

Testing your urine for ketones at home is not as accurate as a blood test. That said, your provider might suggest you use over-the-counter urine ketone test strips to keep an eye on your ketone levels at home.

Frequently Asked Questions

  • What do ketone test strips tell you?

    Ketone strips cannot tell you the exact amount of ketones in your urine. However, they will tell you if your ketone level is high, low, or somewhere in between.

  • What is a normal ketone level in urine?

    A normal level of ketones in your urine depends on your health and lifestyle. In general, healthy people don't have ketones in their urine unless they are following a keto diet.

  • What ketone level is too high?

    A "moderate" to "large" result can be a sign of a problem if you have diabetes. Match your urine ketone test strip to the provided color guide to determine where your result falls.

  • What is a good ketone level for ketosis?

    If you're on a keto diet, your level of ketones will change the longer you have been following it. In the beginning, a "moderate" or "large" level will indicate ketosis. As your body adjusts, you might see only "trace" amounts of ketones when you're in this state.

  • Can stress cause ketones in urine?

    Emotional stress by itself is not likely to cause ketones in your urine, but the stress of an illness can. If you have diabetes, not adjusting your insulin dose to account for being sick or stressed out can also lead to higher levels of ketones in your urine.

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8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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