Test Details
Methodology
High-pressure liquid chromatography (HPLC)
Result Turnaround Time
14 - 21 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
Thymidine phosphorylase Enzyme Analysis is used for the diagnosis of Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE). Thymidine phosphorylase Enzyme Analysis may also be used for assessment of Variants of Uncertain Significance (VUS) identified during genetic testing (e.g. Next Generation Sequencing or Capillary Sequencung testing). MNGIE is an autosomal recessive disorder caused by mutations in the gene encoding thymidine phosphorylase (TP). The disease is characterized clinically by impaired eye movements, gastrointestinal dysmotility, cachexia, peripherl neuropathy, myopathy, and leukoencephalopathy. Molecular genetic studies of MNGIE patients' tissues have reveled mutlitple deletions, depletion, and site-specific point mutations of mitochondrial DNA. TP is a cytosolic enzyme required for nucleoside homeostasis. In MNGIE, TP activity is severely reduced and consequently levels of thymidine and deoxyuridine in plasma are drmatically elevated. MNGIE may benefit from hematopoietic stem cell transplantation.
Special Instructions
This assay currently is not available in New York state.
Limitations
This test was developed and its performance characteristics determined by LabCorp. It has not been cleared or approved by the Food and Drug Administration.
Specimen Requirements
Specimen
Whole blood-ACD
Volume
5 mL
Container
Yellow-top (ACD) tube
Storage Instructions
Ship within 24 hours.
Causes for Rejection
Hemolyzed sample; incorrect collection tube; received frozen