Pyruvate kinase blood test
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 that helps change sugar in the blood (glucose) to energy when oxygen levels are low.
A blood sample is needed.
In the laboratory, white blood cells are removed 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.
Why the Test is Performed
This test is done to detect an abnormal low level of pyruvate kinase. If a person does not have enough of this enzyme, red blood cells break down faster than normal, a condition called hemolytic anemia.
This test helps diagnose pyruvate kinase deficiency (PKD).
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 doctor about the meaning of your specific test results.
What Abnormal Results Mean
A low level of pyruvate kinase confirms pyruvate kinase deficiency.
Veins and arteries vary in size from one patient 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 light-headed
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
Elghetany MT, Banki K. Erythrocytic disorders. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 32.
Gallagher PG. Hemolytic anemias: red cell membrane and metabolic defects In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 164.
Price EA, Otis S, Schrier SL. Red blood cell enzymopathies. In: Hoffman R, Benz EJ Jr, Silberstein LE, et al., eds. Hematology: Basic Principles and Practice. 6th ed. Philadelphia, Pa: Elsevier Saunders; 2012:chap 42.
Review Date: 2/24/2014
Reviewed 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.