- Lavender or pink top tube
- Green top tube is also acceptable
- 5-7 mL of venous blood
Additional information
- Ensure adequate mixing and handle sample gently to prevent hemolysis
- Do not freeze the sample
- Send sample to lab immediately; if delay is expected, refrigerate immediately
- Pyruvate kinase (PK) assay is a quantitative estimation of the enzyme pyruvate kinase activity in blood
- PK is involved in the Embden-Meyerhof pathway of anaerobic glycolysis. PK catalyzes the conversion of phosphoenolpyruvate (PEP) to pyruvate with the production of an adenosine triphosphate (ATP), predominantly in erythrocytes
- Pyruvate kinase deficiency (PKD) may be hereditary or acquired. The hereditary form of PKD is an autosomal recessive disorder, where the deficient PK enzyme causes defective erythrocyte membrane, resulting in increased susceptibility to hemolysis, leading to chronic hemolytic anemia
- The clinical utility of the pyruvate kinase (PK) test includes:
- Aids in the diagnosis and confirmation of PK deficiency
- Aids in differentiating PK deficient hemolytic anemia from other congenital and acquired forms hemolytic anemia
- Assists in evaluation of anemia
- As a screening test for carriers of PK deficiency in hemolytic anemia
- To evaluate in persons with inborn errors of metabolism along with lactate levels
- PK deficiency is the most common cause hereditary nonspherocytic hemolytic anemia. The clinical severity of PK deficiency may range from mild and asymptomatic to severe anemia requiring blood transfusion or splenectomy
- Anemia
- Jaundice
- Kernicterus
- Splenomegaly
- Growth delay
- Failure to thrive
- Cholelithiasis
- Increased risk of intravascular hemolysis during pregnancy or use of certain drugs such as oral contraceptives
- PK deficiency occurs in all races, but is more common among persons of northern European and Chinese ancestry and the Amish group in Pennsylvania. It is estimated to occur at the rate of about 50/1,000,000 in Caucasians
- Factors interfering with test results include:
- Inadequate anticoagulant or inadequate mixing of sample
- Failure to refrigerate sample after collection
- Hemolyzed sample
- Failure to remove WBCs from sample
- Recent blood transfusion (false negative)
- Recent hemolytic event
- Drugs
- Related laboratory tests include:
- Bilirubin
- Complete blood count
- Coombs test
- Donath Landsteiner antibody
- Glucose-6-phosphate dehydrogenase
- Ham test
- Haptoglobin
- Osmotic fragility, RBC
- Pyruvate kinase gene mutation studies
- Urobilinogen
Consult your laboratory for their normal ranges as these may vary somewhat from the ones listed below.
- Conventional (U/g Hb): 9-22 U/g Hb
Conditions associated with increased levels of pyruvate kinase include:
- Carriers of Duchenne's muscular dystrophy
- Myopathy
- Myocardial infarction
- Acquired pyruvate kinase deficiency
- Myelodysplastic disorders
- Acute leukemia
- Other types of anemia
- Aplasias
- Drugs
- Analgesics
- Antipyretics
- Nitrofurans
- Sulfonamides
- Vitamin K (large amounts)
- Congenital pyruvate kinase deficiency
- ARUP Laboratories®. Pyruvate Kinase. [Homepage on the Internet]©2008. Last accessed on September 30, 2008. Available at URL: http://www.aruplab.com/guides/ug/tests/0080290.jsp
- Ayi K et al. Pyruvate kinase deficiency and malaria. N Engl J Med. 2008 Apr 24;358(17):1805-10.
- eMedicine from WebMD®. Pyruvate Kinase Deficiency. [Homepage on the Internet] ©1996-2008. Last updated on July 31, 2007. Last accessed on September 30, 2008. Available at URL: http://www.emedicine.com/ped/TOPIC1971.HTM
- Prchal JT et al. Red cell enzymes. Hematology Am Soc Hematol Educ Program. 2005;19-23.
- Titapiwatanakun R et al. Relative red blood cell enzyme levels as a clue to the diagnosis of pyruvate kinase deficiency. Pediatr Blood Cancer. 2008 Aug 22.