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HelpTest Code TRYPP Tryptophan, Plasma
Reporting Name
Tryptophan, PUseful For
Investigating inadequate tryptophan intake and monitoring dietary treatment
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
PlasmaOrdering Guidance
Body fluids are not acceptable specimens for this test.
For testing urine specimens, order TRYPU / Tryptophan, Random, Urine.
For testing spinal fluid specimens, order AACSF / Amino Acids, Quantitative, Spinal Fluid.
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
Patient Preparation: Patient should fast overnight (4 hours minimum); infants should have specimen collected before next feeding (2-3 hours without total parenteral nutrition if possible).
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube: Green top (sodium heparin)
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions:
1. Collect specimen and place on wet ice. Note: Thrombin-activated tubes should not be used for collection.
2. Centrifuge immediately or within 4 hours of collection if the specimen is kept at refrigerated temperature.
3. Being careful to ensure that no buffy coat is transferred, aliquot plasma into a plastic vial and freeze.
Specimen Minimum Volume
0.3 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Plasma | Frozen | 14 days |
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Reference Values
<24 months: 12-103 nmol/mL
2 years-17 years: 21-114 nmol/mL
≥18 years: 21-108 nmol/mL
Day(s) Performed
Monday through Friday
CPT Code Information
82131
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| TRYPP | Tryptophan, P | 20659-9 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 82955 | Tryptophan | 20659-9 |
| 34619 | Interpretation (TRYPP) | 59462-2 |
| 38056 | 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 daysForms
If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.