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HelpTest 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
Reporting Name
Glucose Phosphate Isomerase, BSpecimen Type
Whole Blood ACD-BSpecimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Whole Blood ACD-B | Refrigerated | 20 days |
Reject Due To
| Gross hemolysis | Reject |
| Fully clotted | Reject |
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.
Method Description
Glucose phosphate isomerase (GPI) interconverts glucose 6-phosphate (G6P) and fructose 6-phosphate (F6P). In this assay, the F6P is then further converted to 6-phosphogluconate through the G6P dehydrogenase (G6PD) reaction resulting in the reduction of nicotinamide adenine dinucleotide phosphate (NADP[+]) to NADPH. The reduction of NADP(+) is measured spectrophotometrically by the increase in absorbance at 340 nm on an automated chemistry analyzer.(Beutler E. Red cell metabolism: A Manual of Biochemical Methods. 3rd ed. Grune and Stratton; 1984: 40-42; Rab MAE, van Wijk R. Enzymes of the red blood cell. In: Rifai N, Chiu RWK, Young I, Burnham CAD, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine. 7th ed. Elsevier; 2023:chap 78)
Specimen Retention Time
28 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
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