Discharge Instructions: Checking for Ketones

Glucose is a kind of sugar from food. Your body needs glucose for energy. If it doesn’t get it, your body starts burning fat. When fat is burned, it makes ketones. Ketones can build up in the blood and urine. This buildup can cause a dangerous condition called ketoacidosis. For this reason, you need to check for ketones at times when you are most at risk. 

When to check for ketones

Check for ketones, especially if you have type 1 diabetes. Do this when any of the following is true:

  • Your blood sugar is above 250 mg/dL.

  • You are ill or under stress.

  • You have diarrhea or stomach pain.

  • You are very thirsty.

  • You need to urinate often.

  • You have a dry mouth.

  • Your breath smells "fruity." 

  • You feel sick or nauseated. Or you have vomited and are becoming dehydrated.

  • You have run out of your usual diabetes medicines and can't get them right away. This is especially true if you use insulin. 

Also check for ketones or if you have type 2 diabetes and are taking a certain type of medicine (SGLT-2 inhibitors).

How to check for ketones

Tips for checking for ketones: 

  • Use testing tablets or strips. Different test kits are available from your drugstore.

  • Depending on the kit, you can check for ketones in your urine or in your blood.

  • Write your test results in a notebook. Show them to your healthcare provider at your next visit.

  • Call your healthcare provider if you test positive for ketones. Follow the instructions in your sick day guidelines on what to do when you have high glucose and ketones. 

Urine tests

Tips for using urine tests: 

  • Follow the package directions carefully.

  • Use a clean container to get a sample of your urine. You can clean a container by washing it with soap and water.

  • Place the test strip in the urine sample. Or pass the strip through your urine stream.

  • Gently shake extra urine off the strip.

  • Wait for the strip to change color. The directions will tell you how long to wait.

  • Compare the strip with the color chart on the bottle or package. This gives you a range for the number of ketones in your urine.

  • Record your results.

Blood tests

Tips for testing your blood: 

  • Use the meter and blood ketone strips as directed by your healthcare provider

  • Record your results.

To learn more

The resources below can help you learn more:

  • American Diabetes Association 800-342-2383 www.diabetes.org

  • Hormone Health Network 800-467-6663 www.hormone.org


Make a follow-up appointment, or as advised.

 When to call your healthcare provider

Call your healthcare provider right away or go to the nearest emergency room if you have any of the following:

  • Fever of 100.4°F (38°C) or higher, or as advised by your healthcare provider

  • Tiredness (fatigue)

  • Dry or flushed skin

  • Nausea or vomiting

  • Stomach pain

  • Shallow breathing

  • A sweet, fruity odor on your breath

  • Confusion

  • If your urine shows moderate to large amounts of ketones 

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