Order Code TPI1 Triosephosphate Isomerase Enzyme Activity, Blood
Specimen Required
Container/Tube:
Preferred: Yellow top (ACD solution B)
Acceptable: Lavender top (EDTA)
Specimen Volume: 6 mL
Collection Instructions: Send whole blood in original tube. Do not aliquot.
Useful For
Evaluating individuals with chronic nonspherocytic hemolytic anemia
Evaluating individuals with early onset neurologic impairment
Genetic counseling for families with triosephosphate isomerase deficiency
Method Name
Kinetic Spectrophotometry (KS)
Reporting Name
Triosephosphate Isomerase, BSpecimen Type
Whole Blood ACD-BSpecimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Whole Blood ACD-B | Refrigerated | 20 days |
Reject Due To
| Gross hemolysis | Reject |
| Fully clotted | Reject |
Reference Values
≥12 months: 1033-1363 U/g Hb
Reference values have not been established for patients younger than 12 months.
Method Description
Triosephosphate isomerase interconverts glyceraldehyde 3-phosphate and dihydroxyacetone phosphate (DHAP). The rate of DHAP formation is measured by further converting it to alpha-glycerophosphate by alpha-glycerophosphate dehydrogenase which results in the oxidation of 1,4-dihydronicotinamide adenine dinucleotide (NADH) to NAD(+). The oxidation of NADH is measured spectrophotometrically by the decrease 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; 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)
Performing Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
82657
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| TPI1 | Triosephosphate Isomerase, B | 44054-5 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| TPICL | Triosephosphate Isomerase, B | 44054-5 |
Day(s) Performed
Tuesday, Thursday
Forms
If not ordering electronically, complete, print, and send a Benign Hematology Test Request (T755) with the specimen.