Ketone Testing

What are ketones?

Ketones (sometimes called acetone) are chemicals that appear in the blood and urine when your body burns fat for energy. Your body burns fat when there is not enough insulin to allow sugar to be burned for energy. Ketones also are produced when you have not eaten enough food to provide the energy your body needs.

Why do I need to test for ketones?

When you have diabetes, ketone testing is very important because ketones can build up in the body. The buildup can cause an emergency condition called ketoacidosis. Ketoacidosis is a serious, life-threatening problem and must be treated immediately.

Frequent ketone tests are important in the first few days after you are first diagnosed with diabetes. You need to make sure that you are taking enough insulin to turn off ketone production.

When should I test for ketones?

You must check for ketones if:

• You have high blood sugar above 240 mg/dL (13.3 mmol/L) after fasting.
• You have high blood sugar above 300 mg/dL (16.6 mmol/L) during the day.
• You feel sick or nauseated (especially if you have vomited). When you are sick, ketones can be present even if your blood sugar is not high.

If you have just been recently diagnosed with diabetes, you usually need to check ketones routinely twice a day (or more often if a test is positive). After the first or second week, if all ketone checks are negative, you can stop routine testing of ketones.

If you have only 1 insulin shot a day, you should do a routine morning ketone test to see if your insulin is lasting a full 24 hours. Ketones will usually be present in the morning if you needed an insulin shot the evening before. If your morning blood sugars vary between very high and very low values, check your ketone level in the morning. Morning ketones can be a sign of a low blood sugar during the night followed by rebounding or bouncing back to a normal or high level by morning.

A method of testing for ketones must be kept in the home (and taken on trips) at all times.

How do I test for ketones?

Tests for checking ketones are available at your local pharmacy. You can check for ketones in the urine or in the blood. Record the test results in a notebook so you don't forget them.

Urine Tests

To check for urine ketones you can use urine test strips. Some commonly used strips are Ketostix or Chemstrip K. The strips are good for about 6 months once a bottle of strips is opened. Strips that are individually wrapped last 2 to 3 years. Ask your pharmacist about the types of urine ketone strips available.

Follow the package directions for testing carefully. Urine ketone tests must be timed exactly using a watch or clock with a secondhand. Have 2 people time and read the strip. This prevents errors due to color blindness or other factors.

Blood Tests

To check for ketones in the blood you need a meter and blood ketone strips. Your provider can show you how to use the meter for measuring blood ketones.

When should I call my health care provider?

Call your health care provider right away (day or night) if:

• The urine ketone test shows medium or high levels of urine ketones.
• The blood ketone test result is higher than 0.6 mmol/L.

If the urine ketone test result is high or the blood test is above 0.6 mmol/L, tell the person answering the phone that the call is urgent.

Call during office hours if:

• You are concerned about the test result.
• You have other questions or concerns.