Sign in →

Test Code TRYPP Tryptophan, Plasma

Reporting Name

Tryptophan, P

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

Investigating inadequate tryptophan intake and monitoring dietary treatment

Method Name

Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)


Ordering 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 Type

Plasma

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

Interpretation

If the result is within the respective age-matched reference range, no interpretation is provided. When an abnormal result is reported, an interpretation may be added, including a correlation to available clinical information, elements of differential diagnosis, and recommendations for additional biochemical testing, if applicable.

Day(s) Performed

Monday through Friday

Report Available

3 to 5 days

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.

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