Vitamin B1 (Thiamine) Test
A vitamin B1 test measures thiamine, a nutrient the body uses to turn food into energy and to keep nerves and the heart working smoothly. Clinicians use this marker to help evaluate thiamine status.
About this test
Vitamin B1, known as thiamine, is a water-soluble vitamin that sits at the heart of how the body releases energy from food, especially carbohydrates. It also supports the healthy working of nerves, muscles, and the heart. The body holds only a modest reserve of thiamine and cannot make it, so a steady supply from the diet matters, and stores can run down faster than people expect during periods of poor intake or higher demand.
The test is done with a simple blood draw at a patient service center. Because most thiamine in the body travels inside red blood cells, laboratories often measure it in whole blood to reflect what is truly on board. A phlebotomist collects the sample from a vein in the arm and sends it to the laboratory. People follow whatever preparation instructions their ordering clinician provides, and the result is read in the context of symptoms and history rather than on its own.
Who commonly orders it
People often look into a thiamine test when exploring symptoms that can be linked to low thiamine, such as unexplained tiredness, changes in balance or sensation, or heart-related complaints. Because thiamine reserves can fall during stretches of poor nutrition, it is frequently considered in the setting of heavy alcohol use, long-standing digestive conditions that affect absorption, recovery from certain weight-loss surgeries, or extended periods of limited eating. A clinician may also want to look at it when several body systems seem involved at once and thiamine could be part of the story.
What this test looks at
A thiamine test reports how much of the vitamin is present in the sample. Thiamine acts as a helper molecule for enzymes that unlock energy from food, so when it runs short the effects can appear anywhere the body's demand for energy is high — including the nervous system and the heart. Measuring the amount available gives a clinician a reference point for whether thiamine deserves attention.
Because the body keeps only a limited store of thiamine, its status can change over a relatively short window, which is one reason a clinician considers recent diet and health events when reading the result.
How clinicians use thiamine in context
Thiamine is often considered as part of a wider nutritional review, and a clinician weighs the result against a person's eating pattern, alcohol use, digestive health, and the symptoms that led to the test. On its own the number is only a starting point; its meaning comes from the surrounding picture.
The result is meant to open a conversation with a clinician rather than to answer a question by itself. From there, a clinician decides in context whether any further evaluation is worth considering.
What to expect at your visit
No appointment is needed. People can walk into a patient service center during open hours, and the draw itself is quick — a phlebotomist takes a small sample from a vein in the arm, and most visits are over in a few minutes. Once the laboratory finishes its analysis, results are posted to the account, where they can be reviewed and shared with a clinician.
Your results
Results will be emailed securely to you as a PDF.
One-time price · physician order included · no insurance needed
Prefer a fuller panel?
A curated bundle groups this test with the markers clinicians most often review alongside it — often better value than single tests.
Frequently asked questions
What does a vitamin B1 test measure?+–
It measures thiamine, the nutrient the body uses to turn food into energy and to support healthy nerves, muscles, and heart function. Laboratories often measure it in whole blood because most thiamine travels inside red blood cells.
Who commonly orders a thiamine test?+–
People exploring symptoms such as unexplained tiredness or changes in balance often discuss it with a clinician, as do those with heavy alcohol use, certain digestive conditions, or a history of weight-loss surgery that can affect absorption.
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, where thiamine is often measured in whole blood.
Why can thiamine status change quickly?+–
The body keeps only a modest reserve of thiamine and cannot make its own, so stores can run down during stretches of poor intake or higher demand. A clinician considers recent diet and health events when reading the result.
Do I need to fast before this test?+–
Fasting is not always required, but people should follow whatever preparation instructions their ordering clinician gives, since individual situations and any panels ordered alongside it can vary.
How much is a Vitamin B1 test?+–
$129, paid once at checkout. The price includes the physician's order this test requires and sample collection at any of 2,300+ Quest patient service centers nationwide.