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Vitamin B6, Plasma (Referred Out) - Saskatoon

Discipline

Biochemistry

Overview

Description

Ordering recommendation

  • To assess vitamin B6 nutritional status.
  • Patient must avoid vitamin supplements for 24 hours before the sample is drawn. The results from a specimen collected following an 8 hour or overnight fast accurately indicates vitamin B6 nutritional status.
  • Infants-draw prior to next feeding.
  • Non-fasting specimen concentration reflects recent vitamin intake.

Test ordering requirements

Preferred Specimen Collection

  • Refer patient to a Dynacare Laboratory Health Services Centre  or a Hospital Test Centre able to process specimens within required time frame

Alias

  • Pyridoxal Phosphate

Specimen Information

Specimen types accepted

  • Plasma

Specimen collection container

Collection procedure

  • Separate plasma from cells within 30 min of collection and aliquot into an amber tube.  Send specimen(s) to St. Paul’s Hospital laboratory frozen or on ice packs.

Required volume

  • Optimal Volume: 4.0 mL full collection tube
  • Minimum Volume: 1 mL plasma

(Submitting the minimum volume makes it impossible to repeat the test or perform confirmatory/reflex testing. In some situations, a minimum volume may require a second collection.)

Transport and stability

  • Plasma aliquot must be frozen or on ice packs within 30 minutes of collection.
  • Vitamin B6 in plasma is stable for 3 days refrigerated and 2 months frozen.
  • Ambient: unacceptable
  • Send specimen to referral lab frozen

Rejection criteria

Testing Information

Clinical interpretation

  • The test measures Pyridoxal 5-phosphate, the biologically active form of vitamin B6

Performance

Methodology

  • Liquid chromatography/tandem mass spectrometry (LC/MS-MS)

Days/times performed

Availability 
  • Shipped Mondays and Wednesdays
  • 11 day turnaround time once received by testing laboratory
Testing site
  • Referred out by St. Paul’s Hospital Laboratory to Dynacare(Ontario)

 

Maximum laboratory time

Results reporting

  • 11 day turnaround time by testing laboratory
  • Shipped Mondays and Wednesdays
     

Last Updated: March 18, 2026