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Vitamin B6 (Pyridoxine) in Serum or Plasma

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

This test measures the amount of vitamin B6 (also called pyridoxine) in your blood. Vitamin B6 is an essential vitamin that helps your body produce important chemicals needed for brain development, immune function, and metabolism.

Quick summary

["Vitamin B6 supports energy, brain health, and red blood cell production."]

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

Key facts at a glance

LOINC
61537-7
Short code
Years vit B6 PhenX
Synonyms
Years vit B6 PhenX
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
phenx
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 Might You Need This Test?

Your healthcare provider may order this test if you have symptoms like fatigue, nerve problems, or unusual cravings for foods like ice or dirt. It may also be checked if you’re taking certain medications that can affect vitamin levels, have certain health conditions (like anemia or liver disease), or are pregnant.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for a few hours before the blood draw. Wear comfortable clothing and plan to rest after the test. Avoid smoking or drinking alcohol right before your appointment.

What Happens During the Test?

A healthcare professional will insert a small needle into a vein in your arm to collect blood. You may feel a slight pinch, but it usually doesn’t cause much discomfort. The blood sample is then sent to a lab for analysis.

What Are the Possible Results?

Results are compared to a general reference range for healthy adults, but individual needs may vary. Low levels may indicate poor absorption, certain medications, or health conditions affecting vitamin B6 metabolism.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Vitamin B6 Level

Frequently asked questions

Could vitamin B6 levels change with diet?
Yes, diet plays a key role. Foods like chickpeas, potatoes, bananas, and fortified cereals are good sources. If your levels are low, your provider may recommend dietary changes or supplements under medical supervision.
Is this test the same as checking for other B vitamins?
No, this test specifically measures vitamin B6 (pyridoxine). Other B vitamins (like B12 or folate) are tested separately. Your provider may order multiple tests if needed for a full vitamin assessment.
What if my results are outside the normal range?
If your results are low, your provider may recommend dietary adjustments, supplements, or further testing to identify the cause. If high, they may investigate potential medications or conditions affecting metabolism.
  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