Pyruvate kinase

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Pyruvate kinase is a blood test to detect abnormally low levels of pyruvate kinase (PK), an enzyme that helps convert glucose to energy when oxygen is low (termed anaerobic metabolism).

PK is found in red blood cells. If the amount of PK is deficient, the red blood cells break down more rapidly than usual. This destruction can result in hemolytic anemia, or too few oxygen-carrying red blood cells.

PK

Blood is drawn from a vein, usually on the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and an elastic band is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the band to fill 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 the laboratory, white blood cells are removed because they can alter test results, and the level of pyruvate kinase is analyzed.

If your child is to have this test performed, it may be helpful to explain how the test will feel, and even demonstrate on a doll. Explain the reason for the test. Knowing the "how and why" may reduce the anxiety your child feels.

When the needle is inserted to draw blood, you may feel moderate pain, or only a prick or stinging sensation. Afterward, there may be some throbbing.

Hemolytic anemia has many causes. It may be present from birth or acquired. A deficiency in pyruvate kinase is fairly rare, and this test helps your health care provider determine the cause of your anemia.

Review Date: 04/29/2005
Reviewed By: Frank A. Greco, M.D., Ph.D., Director, Biophysical Laborartory, The Lahey Clinic, Burlington, MA. Review provided by VeriMed Healthcare Network.