High blood sugar
Your care team may test when blood sugar is higher than 240 mg/dL (13.3 mmol/L).
AI Summary A ketone test measures ketones, chemicals the body makes when it burns fat for energy, in a urine or blood sample. Doctors mainly use it to check for ketoacidosis in people with type 1 diabetes, often when blood sugar is above 240 mg/dL, during illness, with nausea and vomiting, or in pregnancy. Ketones also rise after fasting or on a keto diet. A result does not show liver function. Get urgent help for rapid breathing, fruity breath, or vomiting.
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Ketone Test: Purpose, Procedure, and Results
Medically Reviewed.
A ketone test measures ketones, chemicals the body makes when it burns fat for energy. It uses either a urine sample or a blood sample.
Doctors often use it to check whether someone with type 1 diabetes has had ketoacidosis, a serious problem linked to very high blood sugar.
A ketone result does not diagnose liver disease. Your care team reads it alongside your blood sugar, symptoms, and other tests.
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Ketone basics
What Are Ketones?
Ketones are chemicals your body makes when it uses fat for energy. The liver helps with this. When you have not eaten, it first turns stored fat into ketones or glucose (sugar) to keep your organs fueled.
A very low-carbohydrate eating pattern, called the ketogenic or "keto" diet, also makes the body produce ketones. This process is called ketosis.
A ketone test measures ketones in your urine or blood. It is different from a blood sugar check such as the fasting glucose test.
Ketone testing sits with the urinalysis guides because urine tests help doctors look for signs of infection, kidney problems, diabetes, and liver disease. For ketones, the main purpose is diabetes safety, not liver diagnosis.
Ketone Testing at a Glance
- A ketone test uses a urine sample or a blood sample.
- It may be done to find out whether someone with type 1 diabetes has had ketoacidosis.
- Testing is usually done when blood sugar is higher than 240 mg/dL (13.3 mmol/L), during an illness such as pneumonia, heart attack, or stroke, when nausea and vomiting occur, and during pregnancy.
- The ketogenic diet is a very low-carbohydrate, high-fat eating pattern that produces ketones. People with liver disease should talk with a health care professional before trying it.
- A ketone result does not show how well your liver works.
Reasons for testing
When Doctors Test for Ketones
Ketone testing is most often used to check for ketoacidosis in people with type 1 diabetes. Testing is usually done in these situations.
Illness
Serious illnesses such as pneumonia, heart attack, or stroke are a common reason to check ketones.
Nausea and vomiting
If you have nausea and vomiting, your provider may ask for a ketone test.
Pregnancy
Ketone testing is also done during pregnancy.
Urine and blood testing
How Ketone Testing Is Done
A ketone test uses either a urine sample or a blood sample. Your provider decides which one fits your situation.
In a urine test, the sample may be checked with a dipstick, a thin plastic stick with chemical strips. The strips change color when a substance is present above normal levels. Ketones are one of several substances a urinalysis can check.
If you have diabetes, your care team can tell you when to test at home and which method to use. Ask them before you change how you test.
Understanding your results
What Ketone Results May Mean
Ketones can appear for different reasons. The meaning depends on your blood sugar, your health, and how you have been eating. Ask your care team what counts as a safe level for you.
Ketones with high blood sugar
In someone with type 1 diabetes, ketones together with very high blood sugar can signal diabetic ketoacidosis. Call your care team right away if this happens.
Ketones after fasting
When you go without food, the liver turns stored fat into ketones or glucose to meet your body's energy needs.
Ketones on a keto diet
A very low-carbohydrate, high-fat diet shifts the body toward using fat for fuel and making ketones. This is called ketosis.
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Diabetes safety alert
Warning Signs of Ketoacidosis
These symptoms may happen when blood sugar is very high, a state called diabetic ketoacidosis. For some people, they are the first signs of type 1 diabetes. Get medical help right away if you have them.
Serious warning symptoms
- Deep, rapid breathing
- Dry skin and mouth
- Flushed face
- Fruity breath odor
- Nausea and vomiting, or being unable to keep fluids down
- Stomach pain
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Common Questions
Answers to Common Ketone Questions
What does a ketone test check for?
A ketone test checks for ketones in your urine or blood. Ketones are chemicals your body makes when it burns fat for energy. Doctors often use the test to see whether someone with type 1 diabetes has had ketoacidosis, a serious problem linked to very high blood sugar. The test is different from a blood sugar check, and your provider decides whether a urine or blood sample fits your situation.
When should ketones be tested?
Testing is usually done in four situations: when blood sugar is higher than 240 mg/dL (13.3 mmol/L), during an illness such as pneumonia, heart attack, or stroke, when nausea and vomiting occur, and during pregnancy. Most of these are times when ketoacidosis is a concern. If you have diabetes, your care team can tell you when to test at home and which method to use.
Do ketones in urine mean I have liver disease?
No. A ketone result does not measure liver function. The liver does help make ketones: when you go without food, it turns stored fat into ketones or glucose to keep your organs fueled. But a ketone result does not show how well your liver works. Doctors use liver blood tests and imaging to check liver health, and your care team reads a ketone result alongside your blood sugar, symptoms, and other tests.
Are ketones always a sign of a problem?
Not always. Your body makes ketones after fasting and on a ketogenic diet, where the process is called ketosis. Ketones with very high blood sugar in someone with type 1 diabetes are a different situation. They can signal diabetic ketoacidosis and need urgent attention. Warning symptoms include deep, rapid breathing, dry skin and mouth, a flushed face, fruity breath odor, nausea and vomiting, and stomach pain. Get medical help right away if you have them.
Is the keto diet safe if I have fatty liver disease?
Talk with a health care professional first. The ketogenic diet is a very low-carbohydrate, high-fat eating pattern, and it is highly restrictive. It can help with short-term weight loss and some metabolic markers. Experts still describe it as inconsistent with a liver-friendly diet over the long term, and its effects on liver health are still being studied. People with liver disease should get medical advice before trying it.
Medical disclaimer: LiverDirectory provides educational information and a directory of providers. It does not provide medical advice, diagnosis, or treatment. Always consult a licensed physician regarding any medical condition.