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
Plasma should be separated from cells as soon as possible after collection. Freeze plasma below -20C and ship frozen.
Transport Temperature
Frozen
Specimen Stability
Room temperature: Unacceptable
Refrigerated: 7 days
Frozen: 28 days
Refrigerated: 7 days
Frozen: 28 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis • Received room temperature
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 FDA. 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
Amino Acid analysis is necessary for the diagnosis of a variety of inborn errors of metabolism. These include, but are not limited to, phenylketonuria, tyrosinemia, citrullinemia, non-ketotic hyperglycinemia, maple syrup urine disease, and homocystinuria. The assay is also key for the continued monitoring of treatment plans for these disorders and useful for assessing nutritional status of patients. Our methodology is highly accurate at very low levels as well as at elevated levels.
Performing Laboratory
Quest Diagnostics Nichols Institute-San Juan Capistrano, CA |
33608 Ortega Highway |
San Juan Capistrano, CA 92675-2042 |