The pyruvate kinase test measures the level of the enzyme pyruvate kinase in the blood.
Pyruvate kinase is an enzyme found in red blood cells. It helps change sugar in the blood (glucose) to energy when oxygen levels are low.
How the Test is Performed
A blood sample is needed. In the laboratory, white blood cells are removed from the blood sample because they can alter test results. The level of pyruvate kinase is then measured.
How to Prepare for the Test
No special preparation is necessary.
If your child is having this test, it may help 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 your child's anxiety.
How the Test will Feel
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.
Results vary depending on the testing method used. In general, a normal value is 179 ± 16 units per 100mL of red blood cells.
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your health care provider about the meaning of your specific test results.
What Abnormal Results Mean
A low level of pyruvate kinase confirms PKD.
Veins and arteries vary in size from one person to another and from one side of the body to the other. Obtaining a blood sample 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 lightheaded
- Hematoma (blood buildup under the skin)
- Infection (a slight risk any time the skin is broken)
Gallagher PG. Hemolytic anemias: red cell membrane and metabolic defects. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 161.
Price EA, Otis S, Schrier SL. Red blood cell enzymopathies. In: Hoffman R, Benz EJ Jr, Silberstein LE, Heslop H, Weitz J, Anastasi J, eds. Hematology: Basic Principles and Practice. 6th ed. Philadelphia, PA: Elsevier Saunders; 2012:chap 42.
Update Date 2/11/2016
Updated by: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.