Vitamin B6 Profile (Pyridoxal 5-Phosphate and Pyridoxic Acid), Plasma
Use
This test is used to determine vitamin B6 status and is useful in patients presenting with progressive nerve compression disorders such as carpal tunnel and tarsal tunnel syndromes. It aids in the assessment of the success of vitamin B6 supplementation programs and the diagnosis and evaluation of hypophosphatasia. The test helps differentiate between hypophosphatasia and dietary supplementation as the cause of elevated pyridoxal-5'-phosphate (PLP) levels.
Special Instructions
Specimens must be protected from light using an amber vial for shipment. Proper patient preparation is critical, including fasting for 12 hours and avoiding vitamin supplementation 24 hours before specimen collection.
Limitations
Vitamin supplementation and nonfasting prior to specimen collection may result in elevated plasma vitamin concentrations, which can impact the interpretation of results. Elevated PLP levels could indicate vitamin B6 supplementation rather than hypophosphatasia, which requires careful clinical correlation.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 95266-3
- 1688-1
- 30552-4
Result Turnaround Time
2-5 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1 mL
Minimum Volume
0.75 mL
Container
Amber vial
Collection Instructions
Centrifuge at 4 degrees C within 2 hours of collection and aliquot into an amber vial. Freeze immediately.
Patient Preparation
Fasting for 12 hours is required; avoid multivitamin or vitamin supplements for 24 hours before specimen collection.
Causes for Rejection
Gross hemolysis, gross lipemia, gross icterus is okay.
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 29 days |