Skip to content

Vitamin B6 (Pyridoxine) Phosphorylated Metabolite, Serum/Plasma

Published: August 9, 2026Updated: August 16, 2026

This test measures the active form of vitamin B6, which is essential for nerve function, red blood cell production, and metabolism. Low levels may indicate deficiencies or certain medical conditions.

Quick summary

["Vitamin B6 deficiency can affect how your body processes nutrients and supports nerve health."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
62236-5
Short code
Pyridoxal Phos SerPl-sCnc
Synonyms
Pyridoxal Phos SerPl-sCnc
Category
electrolyte
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
44
Ref high
147
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
84075
SNOMED
27550007
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order this test if you have symptoms like nerve pain, anemia, or unusual fatigue. It can also be part of a broader evaluation for vitamin deficiencies or metabolic disorders.

What to Expect Before the Test

No special preparation is needed, but you may fast for 8–12 hours if instructed. Bring a list of medications to your appointment, as some can affect results.

What the Results Mean

Results help assess whether your body is getting enough vitamin B6. Abnormal levels may signal deficiencies or underlying health issues requiring further testing or treatment.

Common Reasons for Testing

This test is often used alongside other vitamin B6 tests (like total B6) to diagnose deficiencies, especially in people with chronic illnesses, malabsorption issues, or certain genetic disorders.

Reference range

Adult: 44-147 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Pyridoxal Phosphate (PLP) in Serum/Plasma

Frequently asked questions

How long does it take to get results from this test?
Results are typically available within 1–3 business days, depending on your lab’s processing time. Your healthcare provider will contact you once they’re ready.
Can I take vitamin B6 supplements before the test?
Yes, but avoid taking high-dose supplements (especially megadoses) 24–48 hours before testing, as they may affect results. Follow your doctor’s advice if you’re unsure.
Does diet affect this test?
Yes, dietary sources of vitamin B6 (e.g., poultry, fish, legumes) can influence results. If your test is part of a metabolic study, your provider may recommend dietary restrictions.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy