Vitamin B6 Test
A vitamin B6 test measures the amount of this nutrient available in your blood, most often as its active form. B6 helps the body process protein and build brain-signaling chemicals, and clinicians use the marker to help evaluate B6 status.
About this test
Vitamin B6 is a water-soluble vitamin that takes part in a remarkable number of the body's chemical reactions. It helps the body break down and use protein, supports the making of neurotransmitters that carry signals in the brain and nervous system, and plays a role in forming hemoglobin, the part of red blood cells that carries oxygen.
The test is done with a simple blood draw at a patient service center. A phlebotomist collects a sample from a vein in the arm, and it is sent to the laboratory.
Test details
| Quest code | 926 |
|---|---|
| Methodology | Chromatography/Mass Spectrometry |
| Sample type | 1 mL frozen plasma |
| Patient preparation | Fast overnight before your blood draw. |
| Collection | Quest patient service center |
Related tests and panels
Quest resources
Additional details
What this test looks at
A B6 test reports how much of the vitamin's active form is present in a blood sample. Because B6 works as a helper molecule in so many pathways — from processing amino acids to supporting nerve signaling — a shortfall can show up in scattered ways rather than one clear pattern. Measuring the circulating amount gives a clinician a reference point for whether B6 belongs in the conversation.
B6 is unusual among vitamins in that both a shortfall and a long-running excess from supplement products can be relevant, which is part of why a clinician looks at the whole picture rather than a single figure.
How clinicians use B6 in context
B6 is often measured as part of a broader look at B-vitamin status, sometimes alongside B12 and folate, because these nutrients overlap in the pathways they support. A clinician reads the result against a person's diet, supplement use, medications, and the symptoms that prompted the test in the first place.
A single measurement is a starting point, not a verdict. It is meant to open a conversation with a clinician, who decides in context whether any further steps are worth considering.
Order online and a physician order is included — no doctor's visit and no insurance needed. Your sample is collected at a Quest Diagnostics patient service center.
Laboratory results should always be interpreted by a licensed clinician who knows your health history. This page is information about a test, not medical advice.
Frequently asked questions
What does a vitamin B6 test measure?
It measures how much vitamin B6 is available in the blood, usually through its active circulating form, pyridoxal phosphate. This reflects the amount of B6 the body has on hand for its many chemical reactions.
Who commonly orders a B6 test?
People exploring symptoms such as tingling, skin or mouth changes, or mood shifts often discuss it with a clinician, as do those with restricted diets, certain digestive conditions, or a habit of taking supplement blends.
How is the sample collected?
Through a routine blood draw at a patient service center. A phlebotomist takes a small sample from a vein in the arm and sends it to the laboratory for analysis.
Can B6 be too high as well as too low?
Yes. B6 is one of the markers where a long-running excess from supplement products can matter as well as a shortfall, which is why a clinician reviews supplement habits when interpreting the result.
Is B6 tested with other vitamins?
Often. Clinicians sometimes look at B6 alongside B12 and folate because these nutrients work in overlapping pathways, giving a fuller view of a person's B-vitamin status.
Can I get the Vitamin B6 test without a doctor's visit or insurance?
Yes. The $119 cash price includes an independent physician's order, so no referral is needed, and insurance is never involved.
Do I need to prepare for this test?
Fast overnight before your blood draw. This is the preparation Quest publishes for this test; if your clinician gives you different instructions, follow theirs.