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HelpTest Code B6PRO Vitamin B6 Profile (Pyridoxal 5-Phosphate and Pyridoxic Acid), Plasma
Useful For
Determining vitamin B6 status, including in persons who present with progressive nerve compression disorders, such as carpal tunnel and tarsal tunnel syndromes
Determining the overall success of a vitamin B6 supplementation program
Diagnosis and evaluation of hypophosphatasia
Differentiating between hypophosphatasia or dietary supplementation as the likely cause of elevated pyridoxal-5'-phosphate (PLP) levels
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| PLP | Pyridoxal 5-Phosphate (PLP), P | Yes | Yes |
| B6PA | Pyridoxic Acid (PA), P | No | Yes |
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name
Vitamin B6 Profile (PLP and PA), PSpecimen Type
Plasma HeparinShipping Instructions
Ship specimen in amber vial to protect from light.
Specimen Required
Patient Preparation:
1. Patient should fast overnight (12-14 hours); infants-should have specimen collected before next feeding. Water may be taken as needed.
2. For 24 hours before specimen collection, patient must not take multivitamins or vitamin supplements.
Supplies: Amber Frosted Tube, 5 mL (T915)
Collection Container/Tube:
Preferred: Green top (sodium or lithium heparin) or plasma gel separator (PST)
Acceptable: None
Submission Container/Tube: Amber vial
Specimen Volume: 1 mL
Collection Instructions:
1. Within 2 hours of collection, centrifuge at 4° C and aliquot into an amber vial.
2. Freeze immediately.
Specimen Minimum Volume
0.75 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Plasma Heparin | Frozen | 29 days | LIGHT PROTECTED |
Reference Values
PYRIDOXAL 5-PHOSPHATE
5-50 mcg/L
PYRIDOXIC ACID
3-30 mcg/L
Interpretation
Levels for fasting individuals falling in the range of 3 to 30 mcg/L for pyridoxic acid (PA) and 5 to 50 mcg/L for pyridoxal 5-phosphate (PLP) are indicative of adequate nutrition.
The following are interpretative guidelines based on PLP and PA results:
If PLP is >100 mcg/L and PA is ≤30 mcg/L:
-The increased PLP is suggestive of hypophosphatasia. Consider analysis of serum alkaline phosphatase isoenzymes (ALKP / Alkaline Phosphatase, Total and Isoenzymes, Serum) and urinary phosphoethanolamine (AAPD / Amino Acids, Quantitative, Random, Urine)
If PLP is >100 mcg/L and PA is 31 to 100 mcg/L or PLP is 81 to 100 mcg/L and PA is ≤30 mcg/L:
-The increased PLP is likely related to dietary supplementation; however, a mild expression of hypophosphatasia cannot be excluded. Consider analysis of serum alkaline phosphatase isoenzymes (ALKP / Alkaline Phosphatase, Total and Isoenzymes, Serum) and urinary phosphoethanolamine (AAPD / Amino Acids, Quantitative, Random, Urine).
If PLP is 51 to 80 mcg/L or PLP is 81 to 100 mcg/L and PA is >30 mcg/L or PLP is >100 mcg/L and PA is >100 mcg/L:
-The elevated PLP is likely due to dietary supplementation.
Clinical Reference
1. Whyte MP, Zhang F, Wenkert D, et al. Hypophosphatasia: Vitamin B6 status of affected children and adults. Bone. 2022;154:116204. doi:10.1016/j.bone.2021.116204
2. Vitamin B6-Fact Sheet for Health Professionals. US Department of Health and Human Services, National Institutes of Health. Office of Dietary Supplements. Updated June 16, 2023. Accessed February 5, 2025. Available at: https://ods.od.nih.gov/factsheets/VitaminB6-HealthProfessional/
3. Sodi R, Taylor A. Vitamins and trace elements In: Rifai N, Horvath AR, Wittwer CT, eds. Tietz Fundamentals of Clinical Chemistry and Molecular Diagnostics. 8th ed. Elsevier; 2020:466-487
4. Morris MS, Picciano MF, Jacques PF, Selhub J. Plasma pyridoxal 5'-phosphate in the US population: the National Health and Nutrition Examination Survey, 2003-2004. Am J Clin Nutr. 2008;87(5):1446-1454. doi:10.1093/ajcn/87.5.1446
Day(s) Performed
Monday through Thursday, Saturday, Sunday
Performing Laboratory
Mayo Clinic Laboratories in Rochester
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
82542
84207
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| B6PRO | Vitamin B6 Profile (PLP and PA), P | 95266-3 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 61065 | Pyridoxic Acid (PA), P | 1688-1 |
| 4047 | Pyridoxal 5-Phosphate (PLP), P | 30552-4 |