Sugar and metabolism
Bèta-hydroxyboterzuur
The main ketone body in the blood; shows how much the body is running on fat burning.
Everything about this testWhat it measures
When the body cannot use enough glucose (sugar), it switches to burning fat. The liver then makes ketone bodies: beta-hydroxybutyrate, acetoacetate and acetone. These serve as fuel for the brain, among other organs. Beta-hydroxybutyrate makes up the largest part of them. Ketone bodies are acidic; if they rise sharply, the blood can become acidic (ketoacidosis). Urine test strips react mainly to acetoacetate and hardly to beta-hydroxybutyrate; a blood measurement therefore shows the main ketone body more directly.
- Ketoacidosis in newly developed or poorly controlled diabetes
- Ketosis due to fasting, prolonged vomiting, a low-carbohydrate or ketogenic diet or excessive alcohol use
- Rarely: an inborn metabolic disease or a poorly functioning adrenal gland
High
A slightly raised value is usually harmless and fits fasting, a night without food, a low-carbohydrate or ketogenic diet or prolonged heavy exercise. Prolonged vomiting and excessive alcohol use also raise the value. In someone with diabetes, a raised value may point to a shortage of insulin; a strongly raised value can then fit ketoacidosis, even if blood sugar is not very high, for example when using SGLT2 inhibitors (a group of diabetes medicines). Symptoms that go with ketoacidosis are nausea, vomiting, abdominal pain, thirst, frequent urination, deep rapid breathing and drowsiness; this calls for prompt medical assessment.
Low
A low or unmeasurable value is the usual result in someone who eats normally. The body then runs mainly on glucose and makes hardly any ketone bodies. A low value causes no symptoms and has no separate meaning.
If your result is abnormal
With a raised value in someone with diabetes, the GP looks at blood sugar, symptoms and medicines; with symptoms that fit ketoacidosis, immediate referral to hospital follows. With a slightly raised value without diabetes, the GP asks about fasting, eating pattern, alcohol and vomiting, and repeats the measurement after a normal meal if needed.
Reliability
The value reliably shows how many ketone bodies are in the blood at the moment of the blood draw, but that amount changes within hours with eating, fasting and exercise. The result is most meaningful in people with diabetes who feel ill, and always together with blood sugar and sometimes a blood gas test to see whether the blood has become acidic. In people without diabetes and without symptoms, a raised value almost always points to fasting or eating pattern. The value is not suitable for diagnosing diabetes.
Limitations
- Fasting, a low-carbohydrate or ketogenic diet, heavy exercise and alcohol raise the value; how long someone has gone without eating largely determines the result.
- SGLT2 inhibitors can raise ketone bodies while blood sugar is normal; a normal glucose then does not rule out ketoacidosis.
- A result from a mailed-in sample arrives later than a direct measurement; an acute question requires a rapid on-site measurement.
- Reference values differ between laboratories and measurement methods.
How common is this
Ketosis due to fasting or a low-carbohydrate diet is common in healthy people and harmless. Ketoacidosis mainly occurs in people with type 1 diabetes, sometimes as the first sign of the disease, and less often in type 2 diabetes. Dutch figures on how often a raised value occurs in people without diabetes are lacking.
Who is this useful for
The result is mainly meaningful in people with diabetes who feel ill, are vomiting or have high blood sugar, and when following a ketogenic diet under medical supervision. In people without diabetes and without symptoms, a raised value usually only says something about fasting or eating pattern.
Downsides and risks
- A rise due to fasting or a low-carbohydrate diet can cause unnecessary worry.
- A mailed-in sample only gives a result later; with acute symptoms, you should not wait for it.
Sources
Always discuss an abnormal result with your GP. If a result is strongly abnormal, we try to reach you as soon as possible. Read your result yourself as well and contact your GP if in doubt. A test does not make a diagnosis. Read more about risks and results