Vitamin B6 (Pyridoxine) Plasma Concentration (24-Hour Urinary Excretion)
This test measures how much vitamin B6 (pyridoxine), a B vitamin essential for nerve function and metabolism, appears in your urine over 24 hours. It helps assess vitamin B6 levels in your body.
["This test helps check if you have enough vitamin B6 or if it’s being lost in urine, which may indicate deficiencies or metabolic issues."]
Key facts at a glance
- LOINC
- 79325-7
- Short code
- PLP + PL + Vit B6 Pnl SerPl
- Synonyms
- PLP + PL + Vit B6 Pnl SerPl
- Category
- electrolyte
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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 This Test Is Done
Your doctor may order this test if you have symptoms like nerve pain, numbness, or unusual fatigue, which could suggest a vitamin B6 deficiency. It may also be used to monitor conditions like epilepsy, anemia, or certain genetic disorders that affect vitamin B6 metabolism.
What to Expect Before the Test
You’ll collect all urine for 24 hours, starting right after you wake up and ending just before you wake up the next morning. Store the urine in a clean container and keep it refrigerated if possible. Your doctor will provide detailed instructions to ensure accuracy.
What the Test Results Mean
Higher-than-normal results might indicate overuse of supplements or certain medications that increase vitamin B6 excretion. Lower-than-normal results could signal a deficiency, especially if combined with other symptoms. Your doctor will interpret results in the context of your overall health.
Common Conditions Monitored
This test is often used to diagnose or monitor conditions like pyridoxine-dependent epilepsy, homocystinuria, or other metabolic disorders affecting vitamin B6 processing.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Vitamin B6 is crucial for brain and nerve function, red blood cell production, and amino acid metabolism. Deficiencies can lead to neurological issues, anemia, or weakened immune function. Urine tests help identify whether vitamin B6 is being properly absorbed or excreted in your body.
Short name
Vitamin B6 Urine Test (24 hr)
Frequently asked questions
How long does it take to get my test results?
Can I take vitamin B6 supplements before the test?
What if my urine test shows abnormal vitamin B6 levels?
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