Test ID 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
608419Useful 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, BSpecimen Type
Whole Blood ACD-BSpecimen Stability Information
Specimen Type | Temperature | Time | |
---|---|---|---|
Whole Blood ACD-B | Refrigerated | 20 days |
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.
Cautions
Recent transfusion may mask the patient’s intrinsic enzyme activity and cause unreliable results.
Reticulocytosis from any cause can mask some glucose phosphate isomerase (GPI) deficiency cases by raising the activity level. Comparison to other red blood cell (RBC) enzyme activity levels or correction for reticulocytosis may be useful.
Day(s) Performed
Weekly
Report Available
5 daysPerforming Laboratory

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