Test 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, HPLC) 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
UrineNecessary 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
≤35 months: 14-315 nmol/mg creatinine
3-8 years: 10-303 nmol/mg creatinine
9-17 years: 15-229 nmol/mg creatinine
≥18 years: 18-114 nmol/mg creatinine
Day(s) Performed
Monday through Friday
Performing Laboratory

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. This test 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.