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 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.
Who might consider this test?
- Frequently considered in the setting of heavy alcohol use
- Long-standing digestive conditions that affect absorption
Test details
| Quest code | 5042 |
|---|---|
| Methodology | Chromatography/Mass Spectrometry |
| Sample type | 2 mL whole blood |
| Patient preparation | Fast overnight before your blood draw. |
| Collection | Quest patient service center |
Reference range
78-185 nmol/L
Reference ranges are general guidance. The range printed on your own laboratory report is the one that applies to your result.
Related tests and panels
Quest resources
Additional details
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.
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 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 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.
How much is a Vitamin B1 test?
$119, paid once at checkout. The price includes the physician's order this test requires and sample collection at a Quest patient service center.