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HelpTest ID TRYPU Tryptophan, Random, Urine
Useful For
Aiding in the screening and monitoring of Hartnup disease
Highlights
Determination of tryptophan by conventional amino acid profiling methods (ninhydrin based, high-performance liquid chromatography) is hampered by coelution with other compounds. This test utilizes liquid chromatography tandem mass spectrometry to quantify tryptophan and is interference free.
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name
Tryptophan, USpecimen 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 | Special Container |
|---|---|---|---|
| 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
Performing Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
82131
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| TRYPU | Tryptophan, U | 28608-8 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 83823 | Tryptophan, U | 28608-8 |
| 34618 | Interpretation (TRYPU) | 59462-2 |
| 113131 | Reviewed By | 18771-6 |
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.Report Available
3 to 5 daysNY State Approved
YesForms
If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.