what are ketones in blood

Ketones in the blood are acidic chemicals your liver makes when your body burns fat instead of glucose (sugar) for energy. Small amounts are normal, but high levels can be dangerous and may signal a serious condition called diabetic ketoacidosis (DKA), especially in people with diabetes.

What ketones in blood are

Ketones (also called ketone bodies) mainly include acetoacetate, beta‑hydroxybutyrate, and acetone, which circulate in your blood as an alternative fuel. They are produced when your cells cannot get enough glucose, such as during fasting, low‑carb or ketogenic diets, prolonged exercise, or when insulin is very low in diabetes.

When ketones are normal vs. risky

Low or “trace” ketones can be a normal response to fasting or a ketogenic diet, as your body switches to fat burning. Persistently high ketone levels, especially together with high blood sugar and symptoms like nausea, vomiting, abdominal pain, deep breathing, or confusion, suggest possible ketoacidosis and need urgent medical care.

Why doctors check blood ketones

Blood ketone tests are used to detect and monitor DKA, a life‑threatening complication that mostly affects people with type 1 diabetes but can also occur in type 2. Testing is often recommended when someone with diabetes has high blood sugar, feels unwell, has an infection, or is on a very low‑carb diet and develops symptoms.

Typical blood ketone ranges

Guides from diabetes resources describe rough ranges like: below about 0.6 mmol/L as normal, 0.6–1.5 mmol/L as slightly raised, 1.6–2.9 mmol/L as moderately high, and 3.0 mmol/L or more as very high and emergency‑level in the right clinical context. Exact “normal” values vary by person and situation, so targets should always be confirmed with a healthcare professional.

Quick Scoop

• Ketones in blood = fat‑derived acids used as backup energy when glucose is low or unusable.

• Small amounts can be normal (fasting, keto diet, exercise); high levels can make the blood too acidic.

• In diabetes, high ketones plus high blood sugar can mean DKA, which is a medical emergency.

• Home meters and lab tests can measure blood ketones to guide when to seek urgent care.

If you have diabetes or feel very unwell and suspect high ketones, seek immediate medical help rather than waiting for symptoms to pass.

Information gathered from public forums or data available on the internet and portrayed here.