How to Test Your Urine for Ketones

Instructions for Using Home Urine Ketone Tests

Urine ketone testing 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, 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.

What Causes DKA?

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 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"

Self-testing ketones via the urine generally is considered less accurate than blood ketone testing, but when done carefully it can yield reliable results that can be used to determine if further steps should be taken.

How to Choose Ketone Test Strips

There are many brands of urine ketone test strips available over the counter 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 healthcare 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 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, these substandard 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 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 instead.

ketone testing strips
Verywell Health / JR Bee

Saturating the Test Strip

There are two ways to saturate a 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 cleansing 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 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 strip to the color chart that comes with the test kit; this will give you a range of the amount of ketones in your urine.

If it appears 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 again in a few hours.

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

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

Tips for Accuracy

Testing urine for ketones isn't as accurate as testing blood. The results can vary depending on how diluted your urine is, for example. However, if it's your preferred way to test, 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. Test in the early morning or after dinner. Research has found that these are the most reliable times of day to test urine.
  4. If you have trouble distinguishing colors, ask a friend or family member to help you interpret your test results.
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4 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.
  1. American Diabetes Association. DKA (ketoacidosis) & ketones.

  2. De boer AH, Hoppentocht M. Comment on: Inhaled antimicrobial therapy-Barriers to effective treatment, by J.Weers, Adv. Drug Deliv. Rev. (2014). Adv Drug Deliv Rev. 2015;85:e1-2. doi:10.1016/j.addr.2014.08.013

  3. Cleveland Clinic. Clean catch urine collection. February 2007.

  4. Urbain P, Bertz H. Monitoring for compliance with a ketogenic diet: what is the best time of day to test for urinary ketosisNutr Metab (Lond). 2016;13:77. doi:10.1186/s12986-016-0136-4

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