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 mL | Plasma | Sodium heparin (Green) | Frozen, ASAP | Separate 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 mL | Plasma | EDTA (Lavender) | Frozen, ASAP | Separate plasma from cells ASAP or within two hours of collection and transfer into a standard aliquot tube and freeze. | |
| 1 mL | Plasma | ACD A or B (Yellow) | Frozen, ASAP | Separate 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 |
|---|---|
| Ambient | Unacceptable |
| Refrigerated | After separation from cells: 24 hours |
| Frozen | After 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 | <700 | nM |
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.