How to Test Your Urine for Ketones

Instructions for Using Home Urine Ketone Tests

Are you on a diet where part of the goal is to be in nutritional ketosis? Some diets, such as the Atkins Diet, recommend testing to find out whether your body is generating ketones. The easiest and least expensive way to do this is to test your urine using Ketostix or a similar testing strip. Although it is not the most accurate method, it can be helpful for home testing, especially when you're new to a ketogenic diet.

Individual response varies, so different amounts of carbohydrate will result in nutritional ketosis for different people. As well, you may be eating something that is higher in carbohydrate than you realized. Ketone testing can provide information to help you individualize your diet. It also provides motivation to stay in ketosis.

Nutritional Ketosis vs. Ketoacidosis

People with diabetes test ketone levels to check for ketoacidosis, which is a serious condition. They will interpret the reading much differently. The amount of ketones generated during a ketogenic diet is much lower than the dangerous level seen in diabetic ketoacidosis. If you have diabetes, discuss your diet plan with your doctor.

How to Use Ketone Testing Strips

In order to test your urine, you will need ketone urine testing strips. There are many brands available, such as Ketostix and Chemstrip. The name Ketostix is often used to refer to any ketone testing strip, no matter the manufacturer. Whichever you buy, read the product insert in detail to see if their recommendations vary from generic instructions. Also, note that the test will be difficult to interpret if you are colorblind. You may need to ask a friend or family member to check your reading.

ketone testing strips
Verywell Health / JR Bee

A study found the most reliable time of day to test the urine during a ketogenic diet is in the early morning or post-dinner urine.

When you're ready to test, follow these steps:

  1. You can either pass the test end of the strip through your urine as you urinate (be sure to wet it entirely), or collect urine in a clean, dry container and dip the test strip in.
  2. Shake off excess drops of urine.
  3. Wait for 15 seconds or whatever time is stated on the brand of test strips you are using.
  4. Compare the color on your strip to the color array on the side of the bottle.

Any color other than the original beige means there are some ketones in your urine. The closer the color is towards deep purple, the more ketones there are in your body. This does not necessarily mean that the darker the better. Some people find that a low-to-mid level of ketosis is the "sweet spot" for weight loss and feeling good.

Drawbacks of Urine Ketone Testing in a Ketogenic Diet

Urine ketone testing is notoriously unreliable. That is because the level of ketones in the urine doesn't necessarily reflect the level in the blood. For example, the dilution of your urine makes a huge difference.

Also, as time goes on, people on ketogenic diets tend to have lower levels of ketones in their urine. The thinking is that the body gets better at recycling them over time, and doesn't excrete excess acetone as much. Blood tests of ketones are much more reliable, however, the test strips are very expensive.

More recently, some people on ketogenic diets have been using breath analyzers. Ketonix is among the best known that is made for consumers to use at home.

Tips for Ketone Testing Kits

While they are not entirely accurate, you can improve the results of your ketone urine tests by keeping a few things in mind.

  1. Check the expiration date on the testing kit. An expired kit can give you false results.
  2. Be sure to store your test strips with the lid tightly closed. Any moisture or long exposure to air will cause the strips to work improperly.
  3. If you are dehydrated, the urine ketone concentration will obviously higher and give you a "false positive." This often happens to a mild degree in the morning. Likewise, if you are drinking a lot of fluids, the ketone concentration will be lower and give you a "false negative."
  4. If you find yourself frustrated with urine testing because of inconsistencies, consider either not testing or trying a blood ketone test instead.
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