Blood Ketones
At a Glance
Why Get Tested?
To determine whether excessive ketones are present in the blood, to detect diabetic ketoacidosis (DKA), to detect alcoholic ketoacidosis and to monitor ketogenic diet therapy used in the treatment of epilepsy.
When to Get Tested?
When you have symptoms associated with ketoacidosis or being monitored on a ketogenic diet.
Sample Required?
A blood sample taken from a vein in your arm or a drop of blood from your finger.
Test Preparation Needed?
No test preparation is needed.
The Test Sample
What is being tested?
This test measures the amount of ketones in the blood. Ketones are produced during the bodies processing (metabolism) of fats. They are made when glucose is not available to the body’s cells as an energy source. When fatty acids are metabolised, ketones build up in the blood, causing first ketosis, and then ketoacidosis, a form of metabolic acidosis. This condition is most frequently seen with uncontrolled type 1 diabetes and can be a medical emergency.
There are three ketones or ketone bodies, acetoacetate, acetone, and beta-hydroxybutyrate, a reduced form of acetoacetate. Beta-hydroxybutyrate is the main ketone present in severe diabetic ketoacidosis (DKA). Ketone tests measure one or more ketone bodies and therefore their results may be different.
Blood testing gives a snapshot of the amount of ketones that have accumulated at the time that the sample was collected. Urine ketone testing shows recent rather than current blood ketones. Urine testing is much more commonly used than that for blood ketones. It may be performed by itself, with a urine glucose test, or as part of a a range of tests in urine called urinalysis. The urine methods measure either acetoacetate or both acetoacetate and acetone but they do not detect the other ketone beta-hydroxybutyrate.
Blood ketones can be measured in a laboratory or with a handheld monitor. The laboratory test uses serum or plasma, the liquid portion of the blood after the cells have been removed, to measure acetoacetate and/or beta-hydroxybutyrate. When whole blood from a fingerprick is tested for ketones using a handheld monitor, the monitor measures beta-hydroxybutyrate. This test may sometimes be done at a person’s bedside in a hospital and with the appropriate test device by a person at home.
How is the sample collected for testing?
A blood sample is obtained by inserting a needle into a vein in the arm, or by pricking a finger
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
The Test
How is it used?
Blood ketones are mainly used to screen for, detect, and monitor diabetic ketoacidosis (DKA) in people with type 1 and sometimes type 2 diabetes. DKA can occur when a diabetic’s blood sugar is markedly increased, often due to illness, severe infection, pregnancy.
Diabetic ketoacidosis (DKA) is seen with acute (rapid onset) hyperglycemia, a severe lack of insulin, and a disruption of the body’s acid-base balance. Excess ketones and glucose are put into the urine by the kidneys in an effort to flush them from the body. This causes increased urination, thirst, dehydration, and a loss of electrolytes. The affected person may also experience symptoms such as rapid breathing, shortness of breath, a fruit-scent to the breath (the smell of some of the ketones), feeling sick, vomiting, tiredness, confusion, and eventually coma. Ketosis and ketoacidosis may also be seen with starvation, alcoholism, and with high-fat low-carbohydrate diets.
Blood ketones are sometimes used, with other tests such as blood gases, glucose, and electrolytes to detect ketoacidosis in those who do not have diabetics but have signs and symptoms of diabetic ketoacidosis (DKA) due to, for example, ingestion of excessive amounts of alcohol.
When is it requested?
Blood ketone tests may be used when a diabetic has symptoms of DKA and may also be performed whenever there is the potential for DKA to develop, such as when a diabetic is sick or pregnant. Some signs and symptoms of ketoacidosis include:
- increased urination, excessive thirst
- dehydration, loss of electrolytes
- rapid breathing, shortness of breath
- a fruit-scent to the breath
- nausea, vomiting
- fatigue
- confusion
- sometimes coma
In non-diabetics, blood ketones are usually requested when the patient has symptoms of ketosis or ketoacidosis.
What does the test result mean?
If blood ketone concentrations are increased then the person has some degree of ketosis or ketoacidosis. If concentrations are low or normal then the person either does not have excess ketone production or the ketone body that is elevated is not being detected by the test method used.
Is there anything else I should know?
Recent studies have shown that serum ketones and beta-hydroxybutyrate testing are both effective in diagnosing diabetic ketoacidosis. Beta-hydroxybutyrate testing is not available in most laboratories.
Common Questions
Ask a Laboratory Scientist
Article Sources
NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
