Phenylalanine, Quantitative, Plasma
Use
The Phenylalanine, Quantitative, Plasma test measures the level of phenylalanine in plasma and is critical in diagnosing and managing phenylketonuria (PKU) and other amino acid metabolism disorders. Phenylalanine is an amino acid essential for protein synthesis, and its levels can be indicative of metabolic conditions that may require dietary modifications or therapeutic interventions.
Special Instructions
Blood spots on filter paper are not an acceptable specimen type. This test is not to be used for newborn screening. Plasma reference ranges will be applied to all specimen types. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested.
Limitations
This test was developed by LabCorp and its performance characteristics have not been cleared or approved by the US Food and Drug Administration (FDA).
Methodology
Mass Spectrometry
Biomarkers
LOINC Codes
- 14875-9
- 14875-9
- 2765-6
- 49549-9
Result Turnaround Time
3-5 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
0.5 mL
Minimum Volume
0.25 mL
Container
Preferred: Frozen plasma from green-top (sodium heparin) tube. Acceptable: Frozen plasma from green-top (lithium heparin) tube, frozen plasma from lavender-top (EDTA) tube or frozen plasma from PPT™.
Collection Instructions
Separate plasma from cells. Transfer specimen to plastic transport tube before freezing.
Storage Instructions
Centrifuge, remove plasma from cells, and freeze immediately.
Causes for Rejection
Gross hemolysis; room temperature or thawed specimens; specimens collected in yellow-top (ACD) tubes
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Unstable |
| Refrigerated | Unstable |
| Frozen | 14 days |