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Test Code GPIC Glucose Phosphate Isomerase Enzyme Activity, Blood


Specimen Required


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

-HAEV1 / Hemolytic Anemia Evaluation, Blood

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


Useful For

Evaluating individuals with Coombs-negative chronic hemolysis as a part of a profile

Method Name

Only orderable 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

Glucose Phosphate Isomerase, B

Specimen Type

Whole Blood ACD-B

Specimen Stability Information

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

Reference Values

Only orderable 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: 40.0-58.0 U/g Hb

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

Interpretation

Most clinically significant hemolytic anemias due to glucose phosphate isomerase (GPI) deficiency are associated with activity levels under 30% of mean normal; however, some clinically affected patients can have higher activity due to reticulocytosis. Heterozygous individuals usually show 40% to 60% of mean normal activity and are hematologically normal.

 

Variably of increased GPI activity is seen when young red blood cells are produced in response to anemia (reticulocytosis) or in newborns.

Clinical Reference

1. Manco L, Bento C, Victor BL, et al. Hereditary nonspherocytic hemolytic anemia caused by red cell glucose-6-phosphate isomerase (GPI) deficiency in two Portuguese patients: Clinical features and molecular study. Blood Cells Mol Dis. 2016;60:18-23

2. Mojzikova R, Koralkova P, Holub D, et al. Two novel mutations (p.(Ser160Pro) and p.(Arg472Cys)) causing glucose-6-phosphate isomerase deficiency are associated with erythroid dysplasia and inappropriately suppressed hepcidin. Blood Cells Mol Dis. 2018;69:23-29

3. Fairbanks VF, Klee GG: Biochemical aspects of hematology. In: Burtis CA, Ashwood ER, eds. Tietz Textbook of Clinical Chemistry. 3rd ed. WB Saunders Company, 1999;1642-1646

4. Koralkova P, van Solinge WW, van Wijk R: Rare hereditary red blood cell enzymopathies associated with hemolytic anemia-pathophysiology, clinical aspects and laboratory diagnosis. Int J Lab Hematol. 2014;36:388-397

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

84087

LOINC Code Information

Test ID Test Order Name Order LOINC Value
GPIC Glucose Phosphate Isomerase, B 44050-3

 

Result ID Test Result Name Result LOINC Value
GPICL Glucose Phosphate Isomerase, B 44050-3

Day(s) Performed

Weekly

Report Available

5 days