Vitamin B6 (Pyridoxine) Metabolite – Pyridoxal 5'-Phosphate (PLP) in Serum
This test measures the active form of vitamin B6, pyridoxal 5'-phosphate (PLP), in your blood. It helps assess whether your body has enough of this essential nutrient to function properly.
["PLP is a key vitamin B6 form that supports nerve function, red blood cell production, and metabolism."]
Key facts at a glance
- LOINC
- 75042-2
- Short code
- Pyridoxal CSF-sCnc
- Synonyms
- Pyridoxal CSF-sCnc
- Category
- chemistry
- Sample
- csf
- Container
- Sterile tube
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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 doctor may recommend this test if you have symptoms like fatigue, nerve pain, or unusual mood changes that could be linked to vitamin B6 deficiency. It’s also sometimes checked in people with certain medical conditions, such as pregnancy, alcohol use, or certain medications that affect vitamin absorption.
What to Expect Before the Test
No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw a blood sample. If you’re on blood thinners, let your doctor know before the test.
What the Results Mean
Results help determine if your vitamin B6 levels are within a healthy range. Low levels may indicate a deficiency, while very high levels could suggest overconsumption or certain medical conditions.
Common Reasons for Testing
Doctors often check PLP levels in people with symptoms of vitamin B6 deficiency, such as nerve disorders, anemia, or unusual skin rashes. It’s also used in research or monitoring certain treatments that rely on vitamin B6 metabolism.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Low PLP levels may signal a deficiency that could affect nerve function, immune health, or how your body processes other nutrients. High levels might indicate over-supplementation or underlying conditions like liver disease. Always discuss results with your healthcare provider to understand their full implications for your health.
Short name
PLP Level
Frequently asked questions
What causes low PLP levels?
How long does it take to get results?
Can I take vitamin B6 supplements if my PLP level is low?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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