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Test Code PKC Pyruvate Kinase Enzyme Activity, Blood


Specimen Required


Only available as part of a profile. For more information see:

HAEV1 / Hemolytic Anemia Evaluation, Blood

EEEV1 / Red Blood Cell (RBC) Enzyme Evaluation, Blood


Secondary ID

608418

Useful For

Evaluation of nonspherocytic hemolytic anemia as a part of a profile

 

Evaluation of neonatal anemia or jaundice

 

Evaluation of unexplained noninfectious hepatic failure

 

Evaluation of unexplained iron overload

 

Evaluation of unusually severe hemoglobin S trait

 

Evaluation of unusually severe glucose-6-phosphate dehydrogenase deficiency

 

Investigating families with pyruvate kinase deficiency to determine inheritance pattern and for genetic counseling

Method Name

Only available as part of a profile. For more information see:

HAEV1 / Hemolytic Anemia Evaluation, Blood

EEEV1 / Red Blood Cell (RBC) Enzyme Evaluation, Blood

 

Kinetic Spectrophotometry (KS)

Reporting Name

PK Enzyme Activity, B

Specimen Type

Whole Blood ACD-B

Specimen Stability Information

Specimen Type Temperature Time Special Container
Whole Blood ACD-B Refrigerated 20 days

Reject Due To

Gross hemolysis Reject

Clinical Information

Deficiencies of most of the enzymes of the Embden-Meyerhof (glycolytic) pathway, including pyruvate kinase (PK), have been reported. PK deficiency (OMIM 266200) is the erythrocyte enzyme deficiency most frequently found to be a cause of chronic nonspherocytic hemolytic anemia. It is an autosomal recessive disorder and parents of affected patients are typically carriers. Some PK carrier states can exacerbate other red blood cell disorders (ie, coincident glucose 6-phosphate dehydrogenase deficiency or hemoglobin S trait).

 

Clinically significant PK deficiency manifests in widely variable severity ranging from incidental compensated mild normocytic anemia to severe anemia. Neonatal jaundice is very common, and a significant subset of neonates have perinatal complications. Other symptoms include early gallstones and splenomegaly. Iron overload, even in the absence of frequent transfusions, is very common. Rare severe PK deficiency is associated with hydrops fetalis/fetal demise or unexplained noninfectious hepatic failure. Acquired PK deficiency can arise secondary to myeloid neoplasms.

Reference Values

Only available as part of a profile. For more information see:

HAEV1 / Hemolytic Anemia Evaluation, Blood

EEEV1 / Red Blood Cell (RBC) Enzyme Evaluation, Blood

 

≥12 months of age: 5.5-12.4 U/g Hb

Reference values have not been established for patients who are younger than 12 months.

Interpretation

Pyruvate kinase (PK) deficiency is the most easily masked of the red blood cell (RBC) enzyme disorders and can be difficult to classify without complete information, which may require comparison to other RBC enzyme activity levels and/or correlation with results of PKLR gene molecular testing (PKLRZ / PKLR Full Gene Analysis, Varies). Most hemolytic anemias due to PK deficiency are associated with activity levels less than 40% of mean normal. However, some patients with clinically significant hemolysis can have normal or only mildly decreased PK enzyme activity, which, paradoxically, may occur in individuals with the most severe symptoms. Isolated carriers (heterozygotes) may show mildly decreased activity and are typically hematologically normal, although the carrier state may exacerbate other RBC disorders such as glucose 6-phosphate dehydrogenase deficiency, RBC membrane disorders, or hemoglobinopathies. Some alterations in other genes (ie, KLF1) can be associated with decreased PK levels.

 

Elevated PK concentrations can be found in those patients with younger erythrocyte population. This may be due to the patient being a newborn or young RBCs are being produced in response to the anemia (reticulocytosis). Rare PK deficient cases have been associated with minimally increased PK levels; however, comparison to other RBC enzyme activity would be critical in these cases for accurate interpretation.

CPT Code Information

84220

LOINC Code Information

Test ID Test Order Name Order LOINC Value
PKC PK Enzyme Activity, B 32552-2

 

Result ID Test Result Name Result LOINC Value
PKCL PK Enzyme Activity, B 32552-2