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HelpOrder Code TRYPU Tryptophan, Random, Urine
Reporting Name
Tryptophan, UUseful For
Aiding in the screening and monitoring of Hartnup disease
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
UrineOrdering Guidance
Other body fluids are not acceptable specimens for this test. For testing spinal fluid specimens, order AACSF / Amino Acids, Quantitative, Spinal Fluid.
Testing for tryptophan using plasma specimens is available; order TRYPP / Tryptophan, Plasma.
Necessary Information
1. Patient's age is required.
2. Include family history, clinical condition (asymptomatic or acute episode), diet, and drug therapy information.
Specimen Required
Supplies: Urine Tubes, 10 mL (T068)
Container/Tube: Plastic, 10-mL urine tube
Specimen Volume: 2 mL
Collection Instructions: Collect a random urine specimen.
Specimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Urine | Frozen (preferred) | 70 days |
| Refrigerated | 14 days |
Reference Values
<2 months: <241 nmol/mg creatinine
2-35 months: <329 nmol/mg creatinine
3-6 years: <222 nmol/mg creatinine
7-17 years: <218 nmol/mg creatinine
≥18 years: <140 nmol/mg creatinine
Day(s) Performed
Monday through Friday
CPT Code Information
82131
Method Description
Quantitative analysis of amino acids is performed by liquid chromatography tandem mass spectrometry. Patient samples are combined with isotopically labeled internal standard. Following protein precipitation, the supernatant is subjected to hydrophilic-interaction liquid chromatography for the separation of isomers with MS/MS detection of the underivatized amino acids.(Unpublished Mayo method)
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Forms
If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.