Ketones are substances produced in the liver when fat cells break down in the blood. A serum ketone test is a measurement of how many ketones are in the blood.
Blood is most often drawn from a vein. The vein usually used is on the inside of the elbow or the back of the hand.
Theprocedure is done in the following way:
The site is cleaned with germ-killing medicine (antiseptic).
The health care provider wraps an elastic band around the upper arm to apply pressureto the area and make the vein swell with blood.
The health care provider gently inserts a needle into the vein.
The blood collects into an airtight vial or tube attached to the needle.
The elastic band is removed from your arm.
The needle is removed.
The puncture site is covered to stop any bleeding.
In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. Afterward, a bandage may be placed over the area if there is any bleeding.
How to prepare for the test
No preparation is needed.
How the test will feel
When the needle is inserted to draw blood, you may feel slight pain or only a prick or stinging. Afterward, there may be some throbbing.
Veins and arteries vary in size from one patient to another and from one side of the body to the other. Drawing blood from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight but may include:
Excessive bleeding
Fainting or feeling light-headed
Hematoma (blood accumulating under the skin)
Infection (a slight risk any time the skin is broken)
Review Date:
1/26/2013
Reviewed By:
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, Bethanne Black, Stephanie Slon, and Nissi Wang.
