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Vitamin B6 Deficiency Test
This blood test measures vitamin B6, usually as pyridoxal 5-phosphate, to evaluate status. B6 helps metabolize amino acids and make neurotransmitters and hemoglobin, so both low and high levels matter.
Order Vitamin B6 Test
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Order Vitamin B6 Test- Typical turnaround
- 1-3 business days
- Starting price
- From $129
- Results
- Confidential, online
Quick answer
The vitamin B6 test measures the level of vitamin B6 in the blood, most often as its active form, pyridoxal 5-phosphate. Vitamin B6 is needed for processing amino acids, making neurotransmitters, and producing hemoglobin. It is ordered when deficiency or excess is suspected, such as with certain diets, medications, or neurologic symptoms. A blood sample is used, and a healthcare provider interprets the result.
What this test measures
Vitamin B6 is a group of related compounds that the body converts to pyridoxal 5-phosphate, the active coenzyme. This form takes part in more than a hundred reactions, including the metabolism of amino acids, the synthesis of neurotransmitters such as serotonin, and the formation of hemoglobin. It also helps regulate blood sugar.
The test usually measures pyridoxal 5-phosphate in plasma or serum. Because B6 is water-soluble and not stored in large amounts, blood levels reflect recent intake fairly closely. This makes the test sensitive to supplements, and a high result is often related to recent or ongoing supplementation.
Low B6 can occur with poor intake, malabsorption, kidney disease, and some medications. It may be associated with skin changes, anemia, or tingling in the hands and feet. Very high levels, usually from supplements, can also affect nerves, so testing can be useful in both directions.
- Pyridoxal 5-phosphate (PLP)
- Vitamin B6 in plasma or serum
- Pyridoxic acid
- Homocysteine when included
- Complete blood count when paired
- Related B vitamin markers when ordered together
Why people order this test
- Evaluate suspected vitamin B6 deficiency
- Investigate tingling or numbness possibly linked to B6
- Check B6 status when taking high-dose supplements
- Review nutrient levels in malabsorption or kidney disease
- Follow up on skin or blood count changes with poor nutrition
- Assess status before discussing any supplement changes
How to prepare
Fasting may be requested by some laboratories. A blood sample is drawn from a vein, typically at the arm. Tell the ordering provider about any vitamin B6 or multivitamin supplements you take, since recent intake strongly affects the result.
Understanding your results
Results are typically available within one to three business days. The report shows the pyridoxal 5-phosphate level and its reference range. Both low and elevated values can be meaningful, and a healthcare provider interprets them with symptoms and supplement history.
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Frequently Asked Questions
What is pyridoxal 5-phosphate?
It is the active form of vitamin B6 and the form usually measured in blood. It participates in amino acid metabolism, neurotransmitter production, and hemoglobin formation.
Can taking B6 supplements affect the result?
Yes. Recent or ongoing supplementation can raise blood levels significantly, so share your supplement list with the ordering provider.
What symptoms are linked to low B6?
Low levels may be associated with skin changes, anemia, or tingling in the hands and feet, but these symptoms have many possible causes.
Do I need to fast before the test?
Some laboratories ask for fasting and others do not. Follow the instructions included with your order.
Can too much B6 be harmful?
Very high levels, usually from supplements, have been linked to nerve symptoms. Testing can help a healthcare provider assess whether intake is excessive.
Ready to get tested?
Order online and visit a collection site near you, or choose a mail-in kit. No referral and no insurance required.
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