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Thymidine and Deoxyuridine Analytes (Plasma)

CPT

82542

Test Details

Methodology

Liquid chromatography/tandem mass spectrometry (LC/MS-MS)

Result Turnaround Time

10 - 14 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

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.

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

Plasma, frozen

Volume

1.0 mL

Minimum Volume

0.5 mL

Container

Sterile screw capped vial

Collection Instructions

Collect 2-4 mL blood in sodium heparin (green-top), EDTA (purple-top) tube, or ACD (yellow-top) tube. Remove plasma and freeze at -20°C.

Stability Requirements

TemperaturePeriod
Room temperatureUnstable
Refrigerated24 hours
FrozenIndefinitely
Freeze/thaw cyclesNone

Storage Instructions

Store frozen at -20°C and ship frozen.

Causes for Rejection

Thawed sample

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
620173 Thymidine/Deoxyuridine Plasma 79665-6 620168 Thymidine Result 48162-2
620173 Thymidine/Deoxyuridine Plasma 79665-6 620188 Deoxyuridine Result 47957-6
620173 Thymidine/Deoxyuridine Plasma 79665-6 620169 Interpretation N/A
620173 Thymidine/Deoxyuridine Plasma 79665-6 630856 PDF 80563-0
Order Code620173
Order Code NameThymidine/Deoxyuridine Plasma
Order Loinc79665-6
Result Code620168
Result Code NameThymidine Result
UofM
Result LOINC48162-2
Order Code620173
Order Code NameThymidine/Deoxyuridine Plasma
Order Loinc79665-6
Result Code620188
Result Code NameDeoxyuridine Result
UofM
Result LOINC47957-6
Order Code620173
Order Code NameThymidine/Deoxyuridine Plasma
Order Loinc79665-6
Result Code620169
Result Code NameInterpretation
UofM
Result LOINCN/A
Order Code620173
Order Code NameThymidine/Deoxyuridine Plasma
Order Loinc79665-6
Result Code630856
Result Code NamePDF
UofM
Result LOINC80563-0