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Pyruvate Kinase Enzyme
Test CodeLAB01194
Alias/See Also
LAB01194
Mayo TC: PK1
Mayo Test Name: Pyruvate Kinase Enzyme Activity, Blood
Mayo TC: PK1
Mayo Test Name: Pyruvate Kinase Enzyme Activity, Blood
CPT Codes
84220
Preferred Specimen
6 mL Lavendar (EDTA) - Whole Blood
Minimum Volume
1 mL Lavendar (EDTA)
Other Acceptable Specimens
Yellow Top (ACD)
Transport Temperature
Refrigerated
Specimen Stability
Refrigerated: 20 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis
Report Available
1-4 days
Limitations
Pyruvate kinase (PK) activity level can vary from markedly decreased to normal levels in affected individuals due to a compensated increase in enzyme by reticulocytes. Comparison of PK activity levels to other red blood cell enyme activity can be very useful.
Recent transfusion may mask the patient's intrinsic enzyme activity and cause unreliable results.
Because leukocytes also contain PK, if white blood cell (WBC) count is very high, false-negative results may occur due to inability to adequately remove WBCs from the assay.
Recent transfusion may mask the patient's intrinsic enzyme activity and cause unreliable results.
Because leukocytes also contain PK, if white blood cell (WBC) count is very high, false-negative results may occur due to inability to adequately remove WBCs from the assay.
Reference Range
Pyruvate Kinase Enzyme:
> or =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.
> or =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.
Clinical Significance
Pyruvate kinase (PK) deficinecy 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 or correlation with results of PKLR gene molecular testing (PKLRG / Pyruvate Kinase Liver and Red Blood Cell [PKLR] Full Gene Sequencing and Large Deletion Detection, 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.
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.
Performing Laboratory
Mayo Clinic Laboratories