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Test Code TPIC Triosephosphate 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 chronic nonspherocytic hemolytic anemia

 

Evaluating individuals with early onset neurologic impairment

 

Genetic counseling for families with triosephosphate isomerase deficiency

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

Triosephosphate Isomerase, B

Specimen Type

Whole Blood ACD-B

Specimen 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

Clinical Information

Triosephosphate isomerase (TPI) converts dihydroxyacetone phosphate to glyceraldehyde 3-phosphate during glycolysis. Clinically significant TPI deficiency (OMIM 615512, autosomal recessive) is rare and classically manifests as a severe multisystem disorder with early hemolytic anemia and progressive neurologic impairment in infancy. Other clinical features include motor impairment, diaphragm paralysis, cardiomyopathy, and susceptibility to infections. Some cases have isolated hemolytic anemia.

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: 1033-1363 U/g Hb

 

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

Interpretation

Clinically significant hemolytic anemias due to triosephosphate isomerase deficiency are associated with activity levels less than 30% of mean normal. Heterozygous individuals usually show approximately 50% of mean normal activity and are clinically unaffected.

Specimen Retention Time

7 days

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

82657

LOINC Code Information

Test ID Test Order Name Order LOINC Value
TPIC Triosephosphate Isomerase, B 44054-5

 

Result ID Test Result Name Result LOINC Value
TPICL Triosephosphate Isomerase, B 44054-5

Day(s) Performed

Tuesday, Thursday

Report Available

5 days