Vitamin B6 (Pyridoxal 5 Phosphate) (Sendout)

Reference ranges were established using healthy fasting volunteers who abstained from vitamin supplementation for 24 hours prior to collection. Vitamin supplementation and nonfasting may result in elevated plasma vitamin concentrations.

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 >100mcg/L; or -If PLP is >100 mcg/L and PA is < or =30, 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; or PLP is >100 mcg/L and PA is > 100 mcg/L, the elevated pyridoxal 5-phosphate is likely due to dietary supplementation.

Patient Preparation: Fasting-overnight (12-14 hours). Infants-draw prior to next feeding. Patient must not ingest vitamin supplements for 24 hours before the specimen is drawn.

Collection:

Collect 3 mL Blood in GREEN top (Sodium or Lithium Heparin) tube. Wrap in foil after collection to protect from light.

• Also Accepted: Lime PST (wrapped in foil after collection)

Outside Laboratories: Centrifuge sample in a refrigerated centrifuge and transfer plasma to an amber (light-protected) vial within 2 hours of collection. Freeze light-protected plasma at -20°C while awaiting shipment. Transport on dry ice.

Stability: Frozen (Required): 29 days; Refrigerated: Unacceptable; Ambient: Unacceptable.

Reject Due To: Sample not light-protected. Gross hemolysis, lipemia, or icterus okay.

SMART Container Information:

Centrifuge sample in a refrigerated centrifuge and transfer plasma to an amber (light-protected) vial (Mayo Supply T915) within 2 hours of collection. Freeze light-protected plasma at -20°C.

• Note: Whole blood samples that are received without foil/not light-protected may still be processed for testing, as long as they are centrifuged and the plasma transferred to a light-protected aliquot within 2 hours of blood draw.

Sendouts:

• Order Mayo Test: PLP
• Interfaced: Yes [Interface: 601; Worksheet: MAFZ]

Stability: Frozen (Required): 29 days; Refrigerated: Unacceptable; Ambient: Unacceptable.

Reject Due To: Plasma not light-protected. Gross hemolysis, lipemia, or icterus okay.