To determine the amount of ketones (ketone bodies, acetoacetate, beta-hydroxybutyrate, and acetone) in your blood to help diagnose life-threatening problems such as diabetic ketoacidosis (DKA) or alcoholic ketoacidosis (AKA)
When you have symptoms associated with ketoacidosis, such as increased urination, excessive thirst, dehydration, rapid breathing, and shortness of breath
A blood sample drawn from a vein in your arm or from a fingerstick
Ketones or ketone bodies are byproducts of fat metabolism. This test measures the amount of ketones in the blood.
Ketones are produced when glucose is not available to the body's cells as an energy source and/or when the body cannot use glucose as a fuel source because there is no insulin or not enough insulin. Fat is used as fuel instead. When fat is metabolized, byproducts called ketone bodies build up in the blood, causing first ketosis and then progressing to ketoacidosis, a form of metabolic acidosis. This condition is most frequently seen with uncontrolled type 1 diabetes and can be a medical emergency.
Diabetic ketoacidosis (DKA) is associated with sudden and severe high blood glucose (acute hyperglycemia), a severe insulin deficiency, and a disruption of the body's acid-base balance. Excess ketones and glucose are dumped 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. Symptoms may also include rapid breathing, shortness of breath, a fruity scent to the breath, nausea, vomiting, fatigue, confusion, and eventually coma.
Ketosis and ketoacidosis may also be seen with prolonged starvation, alcoholism, and with high-fat, low-carbohydrate diets (keto diets). It may be induced on purpose in some children with epilepsy who have frequent seizures and do not respond to available medications or other treatments.
There are three ketone bodies – acetoacetate, beta-hydroxybutyrate, and acetone.
- Acetoacetate is created first when fat is metabolized.
- Beta-hydroxybutyrate is created from acetoacetate. Beta-hydroxybutyrate is the predominant ketone body present in severe diabetic ketoacidosis (DKA).
- Acetone is a spontaneously created side product of acetoacetate.
Different ketone tests measure one or more ketone bodies, and their results are not interchangeable.
Blood testing gives a snapshot of the status of ketone accumulation at the time that the sample was collected. Urine ketone testing reflects recent rather than current blood ketones. Urine testing is much more common than blood ketones testing. It may be performed by itself, with a urine glucose test, or as part of a urinalysis. The urine methods measure either acetoacetate or acetoacetate and acetone but do not usually detect beta-hydroxybutyrate.
Blood ketones may be measured in a laboratory or with a handheld monitor. The laboratory test uses serum, the liquid portion of the blood, and typically measures acetoacetate. Beta-hydroxybutyrate can be ordered as a separate blood test.
When whole blood from a fingerstick is tested for ketones using a handheld monitor, the monitor measures beta-hydroxybutyrate. This test may be performed at the bedside in a hospital or emergency room, in a healthcare practitioner's office, or performed at home.
How is the test used?
Blood ketones are primarily used to screen for, detect, and monitor a serious, sometimes life-threatening condition called diabetic ketoacidosis (DKA) in people with type 1 and sometimes type 2 diabetes. DKA can occur if you have diabetes and your blood glucose is significantly increased, you are ill or pregnant, have a severe infection, or a variety of other conditions.
Blood ketones are sometimes used, along with other tests such as blood gases, glucose, and electrolytes, to detect ketoacidosis in people without diabetes if they have signs and symptoms of DKA due to, for example, drinking excessive amounts of alcohol.
When is it ordered?
Blood ketone tests may be ordered if you have diabetes and have symptoms associated with diabetic ketoacidosis (DKA) and may also be performed whenever there is the potential for DKA to develop, such as when you are sick or pregnant. With the availability of home monitoring, blood ketones can be ordered as frequently as your healthcare provider recommends. Some signs and symptoms of ketoacidosis include:
- Having to urinate more often, excessive thirst
- Dry skin, cold hands and feet
- Rapid breathing, shortness of breath
- Rapid heart rate
- Fruity scent to the breath
- Nausea, vomiting, sweating
- Coma (sometimes)
In people who do not have diabetes, blood ketones are usually ordered when someone has symptoms associated with ketosis or ketoacidosis, such as those with alcoholic ketoacidosis (AKA) or prolonged starvation.
What does the test result mean?
If blood ketone levels are increased, then you have some degree of ketosis or ketoacidosis.
If levels are low or normal, then you either do not have excess ketone production or the ketone body that is elevated is not being detected by the test method used.
If I have diabetes, can I just test for glucose instead of ketones?
They are related but not the same thing. While increases in ketones are associated with high glucose concentrations, they can also occur with moderate glucose levels in many conditions, such as when you are sick.
Can I test for ketones in my urine instead of my blood?
Can I get diabetic ketoacidosis if I have type 2 diabetes?
Yes, although it is not as common as in type 1 diabetes. It may occur in type 2 diabetes, especially when you have a severe infection or illness. Ketosis and ketoacidosis may also be seen in people without diabetes, such as people with prolonged starvation, alcoholism, and with high-fat, low-carbohydrate diets (keto diets). It may be induced on purpose in some children with epilepsy who have frequent seizures and do not respond to available medications or other treatments.
Can I have ketosis or ketoacidosis and not know it?
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 (DKA). Some healthcare practitioners prefer beta-hydroxybutyrate. In acute DKA, the ketone body ratio (beta-hydroxybutyrate:acetoacetate) rises from normal (1:1) to as high as 10:1. In response to insulin therapy, beta-hydroxybutyrate levels commonly decrease long before acetoacetate levels. However, beta-hydroxybutyrate is not available in all laboratories.