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Vitamin B6 (Pyridoxine) Concentration 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 nutrient that helps your body produce important chemicals involved in metabolism, brain function, and red blood cell production.

Quick summary

["Vitamin B6 supports energy, nerve function, and blood health—low levels may indicate dietary deficiencies or medical conditions."]

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

Key facts at a glance

LOINC
75056-2
Short code
Pyridoxal Phos CSF-sCnc
Synonyms
Pyridoxal Phos CSF-sCnc
Category
electrolyte
Sample
csf
Container
Sterile tube
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
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like fatigue, nerve pain, or unusual mood changes. It could also be checked if you have conditions like anemia, epilepsy, or certain genetic disorders. Additionally, it may be part of a routine check for people with long-term health issues or those taking certain medications that affect vitamin B6 levels.

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast for a few hours before the blood draw, but this depends on your provider’s instructions. Bring a list of medications or supplements you take, as some may affect results.

How the Test Works

A small sample of blood is taken from a vein in your arm. The blood is then sent to a lab where it is analyzed to measure the concentration of vitamin B6. The test uses a sensitive method called immunoassay to detect the vitamin accurately.

What the Results Mean

Results are reported as a concentration of vitamin B6 in the blood. While reference ranges can vary by lab, low levels may suggest poor absorption, dietary deficiencies, or certain health conditions. High levels might indicate over-supplementation or specific metabolic disorders.

Reference range

Adult: 44-147 U/LN/A

Specimen: csf

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

Vitamin B6 Level

Frequently asked questions

What causes low vitamin B6 levels?
Low vitamin B6 levels can result from poor diet (especially if you don’t eat enough foods like meat, fish, or fortified grains), certain medications (like anticonvulsants), alcohol use, or conditions that affect nutrient absorption (such as celiac disease or Crohn’s disease).
What symptoms might low vitamin B6 levels cause?
Symptoms of low vitamin B6 levels may include fatigue, weakness, nerve pain, depression, or unusual mood swings. Some people also experience skin rashes, sores, or anemia. If you experience these symptoms, talk to your provider about testing.
How is vitamin B6 treated or managed?
Treatment for low vitamin B6 levels often involves dietary changes (eating more vitamin B6-rich foods) or supplements under medical supervision. Your provider may recommend specific doses based on your test results and overall health. Avoiding alcohol and certain medications that interfere with vitamin B6 absorption can also help.
  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