Plasma Thymidine Determination




Test Mnemonic

PLTHY

CPT Codes

  • 82542 - QTY (1)

Includes

  • Thymidine
  • Deoxyuridine
  • Interpretation

Performing Laboratory

Medical Neurogenetics


Specimen Requirements

Volume Type Container Collect Temperature Transport Temperature Special Instructions
1 mLPlasmaSodium heparin (Green) Frozen, ASAPSeparate plasma from cells ASAP or within two hours of collection and transfer into a standard aliquot tube and freeze.

Alternate Specimen Requirements

Volume Type Container Collect Temperature Transport Temperature Special Instructions
1 mLPlasmaEDTA (Lavender) Frozen, ASAPSeparate plasma from cells ASAP or within two hours of collection and transfer into a standard aliquot tube and freeze.
1 mLPlasmaACD A or B (Yellow) Frozen, ASAPSeparate plasma from cells ASAP or within two hours of collection and transfer into a standard aliquot tube and freeze.

Minimum Specimen Requirements

Volume Type Container Collect Temperature Transport Temperature Special Instructions
0.5 mL     

Stability

Environmental Condition Description
AmbientUnacceptable
RefrigeratedAfter separation from cells: 24 hours
FrozenAfter separation from cells: 7 days

Days Performed

Varies

Turnaround Time

11 - 15 days

Methodology

Name Description
High Performance Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS) 

Reference Range

Plasma Thymidine Determination
Sex Age From Age To Type Range Range Unit
       Normal<700nM

Special Info

Separate plasma from cells ASAP or within two hours of collection and transfer into a standard aliquot tube and freeze.

Clinical Info

Plasma Thymidine/Deoxyuridine analyte is used for diagnosis of Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE). Thymidine phosphorylase Enzyme Analysis (ENZ06) may also be used for assessment of Variants of Uncertain Significance (VUS) identified during genetic testing (e.g. Next Generation Sequencing or Capillary Sequencing 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, peripheral neuropathy, myopathy and leukoencephalopathy. Molecular genetic studies of MNGIE patients\tissues have revealed multiple deletions, depletion, and site-specific point mutations of mitochrondrial DNA. TP is a cytosolic enzyme required for nucleoside homeostatis. In MNGIE, TP activity is severely reduced and consequently levels of thymidine and deoxyuridine in plasma are dramatically elevated. MNGIE patients may benefit from hematopoietic stem cell transplantation.