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HelpTest Code PLP; SQ: PYRPHO Pyridoxal 5-Phosphate, Plasma
Secondary ID
42359Useful For
Determining the concentration of pyridoxal 5-phosphate in the assessment of vitamin B6 status
Method Name
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name
Pyridoxal 5-Phosphate (PLP), 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 can 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: Green top (sodium or lithium heparin) or plasma gel separator (PST)
Submission Container/Tube: Amber vial
Specimen Volume: 1 mL
Collection Instructions:
1. Centrifuge at 4° C within 2 hours of collection.
2. Aliquot all plasma into amber vial and freeze immediately.
Specimen Minimum Volume
0.75 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Plasma Heparin | Frozen | 29 days | LIGHT PROTECTED |
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Clinical Information
Vitamin B6 is a complex of 6 vitamers: pyridoxal, pyridoxol, pyridoxamine, and their 5'-phosphate esters. Due to its role as a cofactor in many enzymatic reactions, pyridoxal phosphate (PLP) has been determined to be the biologically active form of vitamin B6.
Vitamin B6 deficiency is a potential cause of burning mouth syndrome and a possible potentiating factor for carpal tunnel and tarsal tunnel syndromes. Persons who present chronic, progressive nerve compression disorders may be deficient in vitamin B6 and should be evaluated. Vitamin B6 deficiency is associated with symptoms of scaling of the skin, severe gingivitis, irritability, weakness, depression, dizziness, peripheral neuropathy, and seizures. In the pediatric population, deficiencies have been characterized by diarrhea, anemia, and seizures.
Markedly elevated PLP in conjunction with low levels of pyridoxic acid are observed in cases of hypophosphatasia, a disorder characterized by low levels of alkaline phosphatase and a range of skeletal abnormalities.
Reference Values
5-50 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 upon PLP and PA results:
If PLP is >100 mcg/L and PA is ≤30 mcg/L:
-The increased pyridoxal 5-phosphate is suggestive of hypophosphatasia. Consider analysis of serum alkaline phosphatase isoenzymes (ALKI / 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 < or=30 mcg/L:
-The increased pyridoxal 5-phosphate is likely related to dietary supplementation; however, a mild expression of hypophosphatasia cannot be excluded. Consider analysis of serum alkaline phosphatase isoenzymes (ALKI / 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 pyridoxal 5-phosphate is likely due to dietary supplementation.
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
84207
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| PLP | Pyridoxal 5-Phosphate (PLP), P | 30552-4 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 4047 | Pyridoxal 5-Phosphate (PLP), P | 30552-4 |
Forms
If not ordering electronically, complete, print, and send a General Request (T239) with the specimen.
Method Description
The stable isotope pyridoxal 5-phosphate-d2 and/or pyridoxic acid-d2 is added to plasma as an internal standard. Meta-phosphoric acid solution is then added to precipitate the proteins. Following sedimentation of the proteins, an aliquot of the clarified supernatant fluid is subjected to separation of pyridoxal 5-phosphate, pyridoxic acid, and internal standards from other plasma components by reverse-phase high-performance liquid chromatography with quantitation by tandem mass spectrometry.(Unpublished Mayo method)