What is a ketones in blood test?
A ketones in blood test measures the level of ketones in your blood. Ketones are acids that your body makes when it breaks down fat for energy.
Normally, the cells in your body use blood glucose (sugar) for energy. You get glucose from eating carbohydrates. If your cells can't get enough glucose, your body will break down fat for energy instead. This process produces ketones. If your body breaks down fat too fast, ketones can build up in your blood and urine.
High ketone levels make your blood too acidic. This is a serious condition called ketoacidosis. The most common type of ketoacidosis is a complication of diabetes called diabetic ketoacidosis (DKA). DKA is a medical emergency that often develops quickly and can lead to a coma and be life-threatening.
If you have diabetes, a ketones in blood test can help find high ketone levels early so you can get treatment right away. If your health care provider recommends frequent testing to check for increasing ketone levels, at-home blood testing meters are available that check both glucose levels and ketones. At-home testing for ketones in urine testing may also be an option. Talk with your provider about which is right for you.
Other names: Ketone bodies (blood), serum ketones, beta-hydroxybutyric acid, acetoacetate, nitroprusside test
What is it used for?
A ketones in blood test is mostly used to check for diabetic ketoacidosis (DKA) in people with diabetes. DKA can affect anyone with diabetes, but it is most common with type 1 diabetes. With type 2 diabetes, DKA is less common.
If you have diabetes, a blood ketones test may be used when you are sick or pregnant. You may also be tested if you develop diabetes during pregnancy (gestational diabetes).
If you don't have diabetes, you may have your blood ketones checked if you are at risk for developing ketoacidosis and you have symptoms. You are at risk for ketoacidosis if you have a condition that causes your body to use fat for energy instead of glucose, such as:
Why do I need a ketones in blood test?
You may need a ketones in blood test if you have diabetes and symptoms of DKA, such as:
- Feeling very thirsty
- Urinating (peeing) a lot more than usual
- Nausea and vomiting
- Abdominal (belly) pain
- Dry skin and mouth
- Fast, deep breathing
- Breath that has a fruity smell
- Muscle stiffness or aches
If you don't have diabetes, you may need a ketones in blood test if you have symptoms of ketoacidosis that could be from another condition. You may also need the test if you have symptoms, and you eat a low-carbohydrate "keto" diet for weight loss.
What happens during a ketones in blood test?
A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.
To check blood ketones at home, you may use a blood glucose meter that also tests for ketones. You will use a device to prick your finger. You'll collect a drop of blood on a ketone test strip that is inserted into the meter. The meter will show your ketone levels. Follow the instructions carefully. You can also test for ketones in urine using an at-home kit. Ask your provider how you should test for ketones, when you should test, and what to do if your levels are high.
Will I need to do anything to prepare for the test?
You don't need any special preparations for a ketones in blood test.
Are there any risks to the test?
There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.
What do the results mean?
A normal or negative test result usually means that your body is not making too many ketones and you don't have ketoacidosis. But a normal test result doesn't always rule out diabetic ketoacidosis (DKA). That's because your body makes three types of ketones. If DKA is in the early stages, only one type of ketone will be high, and lab tests often don't measure this type of ketone.
A high or positive test result means you have ketones in your blood. It's normal to have some blood ketones, but if your levels are very high and you have symptoms, you may have ketoacidosis. If you have diabetes, you likely have DKA. If you don't have diabetes, you may have ketoacidosis from alcohol use disorder, malnutrition, not eating for very long periods of time, or other conditions.
Ketoacidosis from any cause must be treated. Treatment may include going to the hospital.
If you have questions about your results, talk with your provider.
Learn more about laboratory tests, reference ranges, and understanding results.
Is there anything else I need to know about a ketones in blood test?
People who eat a low-carbohydrate keto diet to lose weight will have blood ketone levels that are higher, but are not high enough to be ketoacidosis. This condition is called ketosis.
Ketosis doesn't make your blood too acidic because your body is able to use the ketones, so they don't build up. But it's possible to develop ketoacidosis on a keto diet, so it's important to talk with your provider to see if it's safe for you.
- American Diabetes Association [Internet]. Arlington (VA): American Diabetes Association; c1995–2022. Diabetes and DKA (Ketoacidosis); [ cited 2022 May 19]; [about 5 screens]. Available from: https://diabetes.org/diabetes/dka-ketoacidosis-ketones
- Centers for Disease Control and Prevention [Internet]. Atlanta: U.S. Department of Health and Human Services; Diabetic Ketoacidosis; [reviewed 2021 Mar 25; cited 2022 May 19]; [about 13 screens]. Available from: https://www.cdc.gov/diabetes/basics/diabetic-ketoacidosis.html
- Ghimire P, Dhamoon AS. Ketoacidosis. [Updated 2022 May 11; cited 2022 May 19]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK534848/
- Joslin Diabetes Center [Internet]. Boston: Joslin Diabetes Center; c2022. Ketone Testing; [cited 2022 May 19]; [about 8 screens]. Available from: https://www.joslin.org/patient-care/diabetes-education/diabetes-learning-center/ketone-testing-0
- Mayo Clinic [Internet]. Mayo Foundation for Medical Education and Research; c1998–2022. Diabetic Coma: Overview; [cited 2022 May 18]; [about 8 screens]. Available from: https://www.mayoclinic.org/diseases-conditions/diabetic-coma/symptoms-causes/syc-20371475
- National Heart, Lung, and Blood Institute [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; Blood Tests; [updated 2022 Mar 24; cited 2022 May 19]; [about 8 screens]. Available from: https://www.nhlbi.nih.gov/health-topics/blood-tests
- National Institute of Diabetes and Digestive and Kidney Diseases [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; What is Diabetes?; [reviewed 2016 Dec; cited 2022 May 19]; [about 4 screens]. Available from: https://www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetes
- Merck Manual Consumer Version [Internet]. Kenilworth (NJ): Merck & Co. Inc.; c2018. Diabetes Mellitus (DM) in Children and Adolescents; [reviewed 2020 Sep; cited 2022 May 19]; [about 14 screens]. Available from: http://www.merckmanuals.com/home/children-s-health-issues/hormonal-disorders-in-children/diabetes-mellitus-dm-in-children-and-adolescents
- Paoli A. Ketogenic Diet for Obesity: Friend or Foe? Int J Environ Res Public Health [Internet]. 2014 Feb 19 [cited 2018 Feb 22]; 11(2): 2092-2107. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3945587
- Scribd [Internet]. Scribd; c2022. Ketosis: What is ketosis?; [updated 2017 Mar 21; cited 2022 May 19]; [about 2 screens]. Available from: https://www.scribd.com/document/368713988/Ketogenic-Diet
- Testing.com [Internet]. Seattle (WA).: OneCare Media; c2022. Blood Ketones; [modified 2020 Apr 24; cited 2022 May 18]; [about 10 screens]. Available from: https://www.testing.com/tests/blood-ketones/
- UCSF Medical Center [Internet]. San Francisco (CA): The Regents of the University of California; c2002–2022. Medical Tests: Serum Ketones; [reviewed 2019 Jan 26; cited 2022 May 19]; [about 4 screens]. Available from: https://www.ucsfhealth.org/medical-tests/003498
- University of Rochester Medical Center [Internet]. Rochester (NY): University of Rochester Medical Center; c2022. Health Encyclopedia: Ketone Bodies (Blood); [ cited 2022 May 19]; [about 4 screens]. Available from: https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=167&contentid;=ketone_bodies_serum
- UW Health [Internet]. Madison (WI): University of Wisconsin Hospitals and Clinics Authority; c2018. Test for Ketones (Home Test); [current2022 Mar 9; cited 2022 May 19]; [about 4 screens]. Available from: https://patient.uwhealth.org/healthwise/article/en-us/tf7200
- UW Health [Internet]. Madison (WI): University of Wisconsin Hospitals and Clinics Authority; c2022. Ketones Test; [current 2021 Jul 28; cited 2022 May 19]; [about 8 screens]. Available from: https://patient.uwhealth.org/healthwise/article/en-us/hw7738