Understanding Blood Ketones: What Raises Them and When to Seek Help
Learn what affects blood ketone levels, when high levels are an emergency, and who should monitor them closely.
Safety first: when high ketones are an emergency
If you have diabetes and your blood ketones are above 3.0 mmol/L, you may have diabetic ketoacidosis, a serious medical emergency: seek urgent medical care straight away (in the UK the NHS advises calling 999 or going to A&E). Ketones above 1.5 up to 3.0 mmol/L mean speaking to your diabetes team the same day, even if you feel well. Symptoms like repeated vomiting, deep rapid breathing, abdominal pain, drowsiness or confusion signal the need for urgent medical care at any ketone level, with or without diabetes. If you have these symptoms, do not rely on a web page for guidance; seek urgent care immediately.
Blood ketones are usually measured in millimoles per liter (mmol/L). A normal level is below roughly 0.6 mmol/L. Beta-hydroxybutyrate is the main ketone measured in blood tests, and it's a more reliable indicator than urine ketone sticks, which can lag behind and may read low when it's most crucial to know the true level.
What causes high blood ketones without diabetes
In people without diabetes, ketone levels rise primarily due to a lack of carbohydrates. This can happen during an overnight fast, a very low carbohydrate diet, prolonged exercise, pregnancy, or alcohol consumption. These situations cause the body to switch to burning fat for energy, which produces ketones.
Understanding nutritional ketosis
Nutritional ketosis is a state where the body produces ketones as a result of a low carbohydrate intake. People following ketogenic diets often see blood ketone levels between 0.5 and 3.0 mmol/L. This state is not harmful in itself for most healthy individuals, but it's important not to interpret higher levels as better or more beneficial.
Who should monitor ketone levels closely
Beyond diabetes, there are two groups who should pay particular attention to their ketone levels:
People taking SGLT2 inhibitors: These medications, often used for managing type 2 diabetes, can lead to ketoacidosis even if blood glucose levels are normal or only slightly elevated. This can delay diagnosis and treatment, so monitoring ketone levels can be crucial.
Children during illness: When children experience a long illness with poor eating, their bodies may produce ketones, which can lead to dehydration. Monitoring ketone levels can help in managing their health during such times.
Frequently asked questions
What are ketones?
Ketones are chemicals produced by the liver when the body breaks down fat for energy. This usually happens when there isn't enough sugar (glucose) available.
How can I measure my blood ketone levels?
Blood ketone levels can be measured using a home meter that requires a small blood sample, similar to how blood glucose is tested.
Are high ketone levels always dangerous?
Not always. For people without diabetes, higher ketone levels might occur due to diet or exercise. However, in people with diabetes, high ketone levels can be dangerous and need medical attention.
Can I use urine ketone sticks instead of blood tests?
Urine ketone sticks can be used but are less reliable than blood tests because they may not accurately reflect current ketone levels.
What symptoms should I watch for with high ketone levels?
Look for symptoms like nausea, vomiting, abdominal pain, rapid breathing, or confusion, especially if you have diabetes.
When to see a doctor
If you have diabetes, follow your sick-day plan for blood ketones of 0.6 to 1.5 mmol/L and contact your diabetes team if you feel unwell; above 1.5 up to 3.0 mmol/L, speak to your diabetes team the same day, even if you feel well; above 3.0 mmol/L you may have DKA: seek urgent medical care straight away (in the UK the NHS advises calling 999 or going to A&E). Anyone with raised ketones who has repeated vomiting, abdominal pain, deep or fast breathing, drowsiness or confusion should seek urgent medical attention. If you do not have diabetes and your ketones are raised from diet, fasting or exercise without such symptoms, discuss it at a routine visit.
Disclaimer
This information is intended to educate and inform. Any decisions regarding medical care should be made in consultation with a healthcare professional.