This blood test measures ketones, a byproduct of fat metabolism, in the blood. When you have type 1 diabetes with a high level of ketones in your blood, it's called diabetic ketoacidosis (DKA). DKA is a complication of diabetes that can be fatal if it's not treated.
When you have type 1 diabetes, your body doesn't make enough insulin, a hormone that regulates the metabolism of fat and carbohydrates. Or your body can't properly use insulin to break down the food you eat (type 2 diabetes). When your body doesn't have enough insulin, it breaks down fat for energy instead of glucose, or sugar. The breakdown of fat produces ketones, which can build up in your blood and spill over into your urine if your diabetes is not under control. If your ketone levels are too high, it could cause you to go into a diabetic coma.
Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain. Afterward, the site may be sore.
Certain diets, such as a high-protein diet or one that is high in fat and low in carbohydrates, also can cause increased ketones in your blood. Drinking large amounts of alcohol also can affect your test results.
You might also have a high level of ketones in your blood if you have diabetes and you're sick with a cold or the flu.