Checking Blood Ketones

These instructions are for Children's Hospital of Philadelphia patients who are instructed to check for ketones in their blood.

Instructions for storing ketone strips:

• Keep test strips in the foil package until you are ready to use them.

• Do not store in direct sunlight.

• Keep ketone test strips at a temperature between 39°- 86°F. If they are stored in an area that is too hot or too cold, the ketone test results can be wrong.

Instructions for checking blood ketones:

Checking for ketones is very similar to checking a blood sugar. It is important that you use a blood ketone meter and the strips that match the meter.

• Check for ketones when blood sugar is over 240.

  • If using a continuous glucose monitor, check for ketones if over 240 for more than 3 hours.

• During an illness, check for ketones twice daily, even when blood sugars are in the target range.

• If ketones or vomiting are present, monitor blood sugar and ketones every 2 hours. Follow steps for ketone management.

1. Clean your hands with soap and water or hand sanitizer.

2. Remove the test strip from the foil package.

3. Insert a ketone monitoring strip into the meter.

4. Prick a clean finger with the lancing device your child prefers.

5. Test your child's blood as you normally would for a blood sugar.

6. Wait for your result and use the chart below to understand the ketone level.

Understanding blood ketone results:

If your blood ketone result is 0.0 mmol/L and the blood sugar is higher than 300 mg/dL, repeat both the ketone and blood sugar test with new strips. There could be an error.

Call your healthcare provider for blood ketones 1.0 or higher or with any questions or concerns.

Division of Endocrinology and Diabetes

Reviewed on March 1, 2023, by Meredith Allen MS, RD, CDE, LDN