Diabetes Dialogues

Five Things to Know About Ketones


If you live with diabetes, you have probably heard that ketones are something to watch out for. That they have something to do with the dreaded diabetic ketoacidosis (DKA). But do you really understand what ketones are and why they happen?

It’s scary to think about, sure. But it’s also very important to be in the know about ketones and to be prepared.

1) What are ketones?

If there isn’t enough insulin in your system, you can’t turn glucose into energy. So your body starts breaking down body fat. Ketones are a chemical by-product of this process.

This can occur when people with type 1 diabetes don’t take insulin for long periods of time, when insulin pumps fail to deliver insulin and the wearer does not monitor blood sugar, or during serious illness (in type 1 or type 2) when insulin doses are missed or not increased appropriately for the stress of illness.

Ketones can happen to anyone with diabetes, but the condition is more common in people with type 1.

2) Why are ketones dangerous?

Ketones upset the chemical balance of your blood and, if left untreated, can poison the body. Your body cannot tolerate large amounts of ketones and will try to get rid of them through the urine. Eventually they build up in the blood.

The presence of ketones could be a sign that you are experiencing, or will soon develop, diabetic ketoacidosis (DKA)—a life-threatening medical emergency.

3) When should I test for ketones, and how?

There are several situations in which it is a good idea to check for ketones, usually every four to six hours. Talk to your doctor to know what makes the most sense for you and your diabetes management plan.

  • Your blood sugar is more than 300 mg/dl (or a level recommended by your doctor)
  • You feel nauseated, are vomiting or have abdominal pain
  • You are sick (for example, with a cold or flu)
  • You feel tired all the time
  • You are thirsty or have a very dry mouth
  • Your skin is flushed
  • You have a hard time breathing
  • Your breath smells “fruity”
  • You feel confused or “in a fog”

Ketone test strips are available at your pharmacy. They kits are quick and simple to use—though it is important to follow the instructions closely. Always have test strips on hand and check their expiration date.

Make sure you understand the directions in advance, and ask your doctor or nurse if you would like a demonstration. Generally, the test will involve dipping a strip in a urine sample, waiting for it to change color, then comparing your results to a chart on the packaging. The color will estimate the concentration of ketones in your urine. Remember to record your results!

4) When should I call my doctor for this?

Talk to your doctor immediately if your urine results show moderate or large amounts of ketones. This is a sign that your diabetes is out of control, or that you are getting sick. If you are unable to reach your diabetes care team, head for the emergency room or an urgent care facility.

Share the notes from your log, as this important data will provide clues as to how to treat you and adjust your diabetes management plan.

Small or trace amounts of ketones may mean that ketone buildup is starting. You should increase your intake of fluids (water is best) and take other steps to get your blood sugar levels in check. You should test again in a few hours. Call your doctor if the levels increase.

5) Will exercise help?

Exercise is often a good way to bring down high blood sugar—but not when ketones are present. Never exercise when your urine checks show moderate or large amounts of ketones and your blood sugar is high. It may make your blood sugar level go even higher.

Learn more about ketones