Serum ketones test

 

Alternative Names

Acetone bodies; Ketones - serum; Nitroprusside test; Ketone bodies - serum; Ketones - blood

Definition

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.

How the Test is Performed

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.

Why the Test is Performed

This test is used to diagnose ketoacidosis.

Normal Results

A normal test result would be negative, meaning there are no ketones in the blood.

Normal value ranges may vary slightly among different laboratories. Talk to your health care provider about the meaning of your specific test results.

What Abnormal Results Mean

A test result is positive if ketones are found in the blood. This may indicate:

Risks

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)

Considerations

A diet low in carbohydrates can increase ketones.

References

Khan MI, Weinstock RS. Carbohydrates. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 16.

Seifter JL. Acid-base disorders. In: Goldman L, Schafer AI, eds. Goldman’s Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 120.

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.

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