Join AARP
Join for Just $16 A Year
- Discounts on travel and everyday savings
- Subscription to AARP The Magazine
- Free membership for your spouse or partner
Find the job you want today
Do something every day to help you achieve your goals

A serum ketone test is an important test to determine the levels of a byproduct when your body burns fat.
Ketones are produced when glucose (a form of sugar) isn’t available to supply the body’s cells with energy. This becomes a problem if your body doesn’t have enough insulin to properly digest or use the glucose. When glucose isn’t available, your body uses stored body fat as a source of energy. This releases the ketones that can accumulate in the blood.
If ketones build up in the body, it can lead to ketosis. Ketosis can cause dehydration, dizziness, nausea, and weakness. After that, it can lead to ketoacidosis, a condition that can lead to diabetic coma or even death.
The test is done so your doctor can have an accurate depiction of the levels of ketones in your blood. It is an important test when determining the effects of diabetes, chronic alcoholism, or long-term starvation.
Ketone levels are important for monitoring conditions such as diabetes. The body’s inability to produce adequate amounts of insulin prevents the body from processing sugars properly. The test is especially important for people with diabetes who become sick or pregnant.
According to the Mayo Clinic, keytone buildup has also been linked to low-carbohydrate fad diets, such as the South Beach Diet and the Atkin’s diet (Mayo, 2011).
Do not eat anything for at least four hours before your appointment. Your doctor will inform you if there are any other ways you should prepare for the test.
A serum ketone test is done in a laboratory setting using a sample of the patient’s blood.
The sample is taken at your doctor’s office or a specialized facility. An intravenous needle is placed in the patient’s arm. Several small vials of blood will be taken from the same entry point. The samples are then sent to a laboratory. This could be at the hospital or the samples may be sent away to another facility.
Once the blood draw is done, the patient’s involvement in the test is over. A bandage will be placed over the injection site and can be taken off within an hour of the sample. It may feel tender or sore afterwards, but this typically goes away by the end of the day.
Some blood glucose monitors also test for ketone levels. This provides a reading every time you check your blood sugar levels, which can be helpful for planning exercise or monitoring your ketones on your own.
Ketones can also be tested through a sample of the urine. Testing equipment is available for home use.
Normal results show there are no ketones in the blood.
The presence of ketones in the blood can indicate:
When your test results are available, your doctor will review them with you. This may be over the phone or at a follow-up appointment.
The only complications of the test come from taking a blood sample. A good vein to take the blood sample from may be difficult to find and there may be a slight prick sensation or bruising at the site of the needle insertion. These symptoms are temporary and will go following the test or after a few days.
Written by: Brian Krans
Published on Jun 01, 2012
Updated on Feb 15, 2013
Medically reviewed
by Brenda B. Spriggs, MD, MPH, FACP
|
Enter your symptoms in our Symptom Checker to find out possible causes of your symptoms. Go.
|
|
Enter any list of prescription drugs and see how they interact with each other and with other substances. Go.
|
|
Enter its color and shape information, and this tool helps you identify it. Go.
|
|
Find information on drug interactions, side effects, and more. Go.
|
Member access to health and insurance products and services at AARPhealthcare.com.
Members can get an instant quote with AARP® Dental Insurance administered by Delta Dental Insurance Company.
Members can save on eyewear with AARP® Vision Discounts provided by EyeMed.
Caregiving can be a lonely journey, but AARP offers resources that can help.