URL of this page: http://www.nlm.nih.gov/medlineplus/ency/article/003498.htm
Alternative names
Acetone bodies; Ketones - serum; Nitroprusside test; Ketone bodies - serumDefinition
This test measures the amount of ketones in the blood. Any amount of detectable ketones is considered abnormal.How the test is performed
Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and an elastic band or blood pressure cuff is placed around the upper arm to cause the veins below the band to swell with blood.
A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.
In infants or young children:
The area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding.
How to prepare for the test
Fast for 4 hours before the test.How the test will feel
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.Why the test is performed
This test is used to diagnose ketoacidosis, which is high levels of ketones in the blood. The main causes of ketoacidosis are uncontrolled diabetes, starvation, and alcoholism.
In diabetes, there may not be enough insulin to move glucose into cells. The body then looks for other forms of energy and uses fat as a fuel source. As fats are broken down, acids called ketones build up in the blood and urine. In high levels, ketones are poisonous to body tissue.
The diagnosis is often made in an urgent care center of an emergency department. A patient suspected of having ketoacidosis may have already had a urine test showing ketones in the urine, or a blood test showing low levels of bicarbonate, indicating acid in the blood.
Normal Values
A normal test result would be "negative", meaning there are no ketone bodies in the blood.What abnormal results mean
A test result is "positive" if ketones are found in the blood. This may indicate:What the risks are
The only risks are those associated with the venipuncture.
Special considerations
A diet low in carbohydrates can increase ketone bodies.