A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
Tryptophan
Test Code959
CPT Codes
82131
Preferred Specimen
2 mL plasma collected in a sodium heparin (green-top) tube
Patient Preparation
Collect plasma specimens after an overnight fast (or at least 4 hours after a meal) if possible.
Non-fasting samples are acceptable for pediatric patients.
Minimum Volume
0.25 mL
Other Acceptable Specimens
Plasma collected in: EDTA (lavender-top) tube or lithium heparin (green-top) tube
Instructions
Date of birth must be provided. Plasma should be separated from cells as soon as possible after collection. Freeze plasma below -20ºC and ship frozen.
Transport Container
Plastic screw-cap vial
Transport Temperature
Frozen
Specimen Stability
Room temperature: Unacceptable
Refrigerated: 7 days
Frozen: 30 days
Refrigerated: 7 days
Frozen: 30 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis
Methodology
Chromatography/Mass Spectrometry
FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by the U.S. Food and Drug Administration. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.
Setup Schedule
Set up: Tues, Thurs, Fri; Report available: 6-10 days
Reference Range
≤30 days | 17-85 umol/L |
31 days-23 months | 16-92 umol/L |
2-17 years | 30-94 umol/L |
≥18 years | 40-91 umol/L |
Clinical Significance
Tryptophanuria is a rare autosomal recessive disease associated with mental retardation, neuropsychiatric dysfunction, and photosensitive skin rash.
Performing Laboratory
Quest Diagnostics Nichols Institute-San Juan Capistrano, CA |
33608 Ortega Highway |
San Juan Capistrano, CA 92675-2042 |