Vitamin B6 (pyridoxine) test
Quick answer: This blood test measures vitamin B6, which the body uses for metabolism, nerves and making red blood cells. It is ordered when deficiency is suspected, for example with some medicines, poor diet or alcohol use, or when nerve symptoms suggest too much from supplements.
- SampleBlood
- TakesAbout 5 minutes
- Before the testNo special preparation is usually needed.
How the test is done
- 1You may be asked to fast overnight if the lab prefers
- 2A vein in your arm is cleaned
- 3Blood is drawn into a tube protected from light
- 4The lab measures the active form of B6, called PLP
What your results can mean
Reading your report
Normal ranges differ between labs, so compare your result with the range printed on your report and discuss it with your doctor.
If the result is outside the usual range
A low level can be seen with poor diet, heavy alcohol use, kidney disease or some medicines such as isoniazid for TB. A high level is usually seen with long-term high-dose supplements and can cause numbness or tingling in the hands and feet.
Who usually has this test
People with nerve symptoms, poor diet or alcohol use, those on medicines such as isoniazid, and people taking high-dose B6 supplements.
Risks and aftercare
A small bruise is possible, and you can eat once a fasting sample is taken.
Names and options
Also called: pyridoxine level, PLP test
Listed by the hospital as
- PYRIDOXINE (VITAMIN B6), PLASMA
Questions about this test
Can too much vitamin B6 cause nerve damage?
Yes. Taking high doses of B6 supplements for a long time can cause numbness, tingling or unsteadiness. Symptoms usually improve after the supplement is stopped under a doctor's advice.
Why do some TB medicines need extra B6?
Isoniazid, a common TB medicine, can lower B6 and cause nerve problems. Doctors often prescribe a small dose of B6 alongside it.
Is vitamin B6 used for nausea in pregnancy?
B6 is sometimes used to ease nausea in early pregnancy. Ask your doctor about the right dose before taking it.
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Tamara Hospital & IVF Centre, Rajajinagar
34/3, 10th Cross Road, opp. Vardhaka Sardar Patel School, 1st N Block, 2nd Stage, Rajajinagar, Bengaluru 560010
The hospital is open 24 hours. Call before you come to check the timing for your scan or sample collection.
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This page explains each test in general terms so you know what to expect. It is not medical advice: your doctor decides which tests you need and what your results mean. Reference ranges differ between laboratories. Updated 4 November 2026.