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Test ID PLP Pyridoxal 5-Phosphate, 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

Method Name

Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

Reporting Name

Pyridoxal 5-Phosphate (PLP), P

Specimen Type

Plasma Heparin

Shipping Instructions

Ship specimen in amber vial to protect from light.

Specimen Required

Patient Preparation:

1. Fasting-overnight (12-14 hours) (infants-collect specimen prior to next feeding). Water can be taken as needed

2. For 24 hours prior to 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

Reference Values

5-50 mcg/L

Day(s) Performed

Monday through Thursday, Saturday, Sunday

Report Available

1 to 4 days

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. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information


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


If not ordering electronically, complete, print, and send a General Request (T239) with the specimen.