Vitamin B1 Test
Vitamin B1 Test can be requested without a referral, and this overview covers what to expect. A vitamin B1 test measures the amount of thiamine, a water-soluble vitamin your body needs to turn food into energy and keep nerves working properly. It is usually ordered when a person has symptoms or conditions that suggest low thiamine, such as poor nutrition, heavy alcohol use, or prolonged vomiting.
- Sample type
- blood
- Category
- Vitamin & Mineral
- Turnaround
- 1-3 business days
- Price
- $136
- Referral
- Not required
A vitamin B1 test measures the amount of thiamine, a water-soluble vitamin your body needs to turn food into energy and keep nerves working properly. It is usually ordered when a person has symptoms or conditions that suggest low thiamine, such as poor nutrition, heavy alcohol use, or prolonged vomiting.
What it measures
- Thiamine (vitamin B1) — The main vitamin level being checked in the blood.
- Thiamine diphosphate — The active form of B1 that the body uses; often measured in red blood cells.
- Erythrocyte transketolase activity — An enzyme test that indirectly shows how well B1 is working in cells.
- Lactate and pyruvate — Substances that can rise when B1 is too low for normal energy use.
Who it is for
A clinician may order this test if you have symptoms such as numbness, confusion, or muscle weakness, or if you have a condition that raises your risk of low thiamine. It is not a routine screening test for most healthy adults.
Preparation
No fasting is usually required. Tell your clinician about all medicines and supplements you take, because some can affect the result.
Results and what they mean
Results are reported as a number with a reference range, and sometimes as a red blood cell measurement. Your clinician interprets the result along with your symptoms, diet, and other tests. This is general information only and is not medical advice; discuss your results with a qualified clinician.
How to order this test
- Choose the test and place a confidential order online.
- Select a certified collection site and pick a time that suits you.
- Have your specimen collected — most draws take only a few minutes.
- Review results in a secure portal, typically within 1–3 days.
Preparation, hours, and pricing vary by site; confirm details directly with the lab before your visit.
Availability by state
Direct-access online ordering for the vitamin b1 test is available in most states. It is currently unavailable in 6 states:
Everywhere else you can order confidentially and collect your sample at a certified site. Browse by state →
Frequently asked questions
Do I need to stop eating before this test?
No. Fasting is not normally needed for a vitamin B1 blood test.
Can I take my vitamin supplements before the test?
Ask your clinician first. Some supplements can change the measured level, so timing may matter.
How long until I get results?
Results are typically available within 1 to 3 business days, though this can vary by lab.
What does a low result mean?
A low result may suggest your body does not have enough thiamine, but only your clinician can explain what it means for you.