Sign in →

Test Code GPIC Glucose Phosphate Isomerase 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

608419

Useful For

The evaluation of individuals with Coombs-negative chronic hemolysis

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

Glucose Phosphate Isomerase, 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

The glucose 6-phosphate isomerase (GPI) enzyme interconverts glucose 6-phosphate and fructose 6-phosphate in the second step of glycolysis. GPI deficiency (OMIM 613470) is a cause of nonspherocytic hemolytic anemia and has been reported in patients from varied ethnic backgrounds. As investigational methods have improved, the number of confirmed diagnoses has increased, although the disorder remains rare. Inheritance is autosomal recessive. Clinically significant GPI deficiency manifests in variable severity ranging from mild to severe anemia, with jaundice, gallstones and splenomegaly. Some cases of neonatal death/hydrops fetalis have been reported to be associated with GPI deficiency A subset of patients shows neurologic impairment and granulocyte dysfunction. Heterozygotes are expected to have a normal phenotype.

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: 40.0-58.0 U/g Hb

Reference values have not been established for patients who are younger than12 months of age.

Interpretation

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

 

Increased GPI activity is variably seen when young red blood cells are being produced in response to the anemia (reticulocytosis) or in newborns.

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