Vitamin B1 (Thiamine)
The Vitamin B1 (Thiamine) blood test measures thiamine levels in your body. It helps detect deficiency that can affect energy metabolism, nerves, and heart function.
Turnaround time
2 days
Biomarkers count
1
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Details about Vitamin B1 (Thiamine)
What is the Vitamin B1 (Thiamine) test?
The Vitamin B1 (Thiamine) test measures the level of thiamine in the blood, an essential water-soluble vitamin required for carbohydrate metabolism and energy production. Thiamine plays a key role in converting glucose into energy and supporting normal nerve and muscle function.
Because the body stores very little thiamine, deficiency can develop quickly, particularly in people with poor dietary intake, chronic illness, or increased metabolic demand. Blood testing provides a reliable way to assess thiamine status when deficiency is suspected.
Clinically, this test is used to investigate unexplained fatigue, neurological symptoms, heart problems, and conditions associated with malnutrition or impaired absorption.
Why do I need a test for Vitamin B1 (Thiamine)?
Vitamin B1 deficiency can have serious neurological and cardiovascular consequences if not identified early. It is more common in individuals with high alcohol intake, malabsorption disorders, chronic illness, or those following very restricted diets.
Symptoms are often non-specific in early stages, which means deficiency can go undiagnosed. Testing allows accurate identification and timely intervention before severe complications develop.
You may need a Vitamin B1 test if you experience:
- Persistent fatigue or low energy
- Memory problems or confusion
- Tingling or numbness in hands and feet
- Muscle weakness
- Shortness of breath or heart-related symptoms
- Poor appetite or unexplained weight loss
- History of alcohol excess or malnutrition
Benefits of the Vitamin B1 (Thiamine) test
- Detects thiamine deficiency early
Identifies low levels before neurological or cardiac damage occurs. - Supports investigation of fatigue
Helps determine whether low energy is related to impaired energy metabolism. - Assesses neurological health
Useful when evaluating nerve symptoms or cognitive changes. - Supports cardiovascular assessment
Thiamine deficiency can impair heart function if untreated. - Relevant for high-risk groups
Important for individuals with alcohol dependence or malabsorption. - Guides appropriate supplementation
Ensures thiamine replacement is evidence-based. - Helps prevent severe deficiency syndromes
Reduces risk of conditions such as beriberi or Wernicke’s encephalopathy. - Improves diagnostic accuracy
Provides objective biochemical confirmation.
Step-by-step – How we offer this test
Option 1: Clinic-based blood test (UK-wide)
- Choose your nearest UK clinic
- Attend your appointment
- A clinician draws a blood sample
- Results are processed and reported
Option 2: Home or hotel visit (+£60, UK-wide)
- A qualified phlebotomist visits your location
- Blood sample taken at home or in your hotel
- No need to travel or wait
- Results processed identically to clinic testing
Your results explained
Low Vitamin B1 (Thiamine) levels
Low thiamine levels indicate deficiency, which can impair energy metabolism and damage the nervous and cardiovascular systems.
UK reference range (low):
- < 70 nmol/L
Low levels are associated with fatigue, neuropathy, confusion, and in severe cases, cardiac complications.
Normal Vitamin B1 (Thiamine) levels
Normal levels suggest adequate thiamine availability for energy production and nerve function.
UK reference range (normal):
- 70 – 180 nmol/L
Symptoms within this range are unlikely to be caused by thiamine deficiency.
High Vitamin B1 (Thiamine) levels
High thiamine levels are uncommon and usually related to supplementation. Excess thiamine is generally excreted in urine.
UK reference range (high):
- > 180 nmol/L
High levels are rarely associated with toxicity.
How It Works
Simple steps to get your results
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Visit or Test at Home
Attend one of our UK or London clinics, arrange a home nurse visit, or use a finger-prick kit where available.
Get Your Results
Your sample is analysed by accredited UK laboratories, with secure results delivered directly to you.
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WhatsApp UsHow to Prepare for Your Test
Follow these guidelines for accurate results
Sample Timing
Where possible, attend your blood test between 7am and 12pm. Please wait until any short-term illness or infection has fully resolved before testing. Avoid intense exercise for 24–48 hours beforehand, as this can affect certain markers.
Fasting & Hydration
Fasting is not always required, but some tests may recommend it. If fasting is advised, avoid food for 8–12 hours before your appointment and drink water only. Stay well hydrated, as this helps with sample collection and accuracy.
Medications & Supplements
Continue prescribed medications unless advised otherwise by your clinician. Avoid vitamin, mineral, or biotin supplements for at least 24–48 hours before your test, as these can interfere with results. If you are unsure about any medication or supplement, please let us know before your appointment.
Hormones & Menstrual Cycle
For hormone-related tests, timing within your menstrual cycle may be important. If relevant, follow any specific guidance provided on your test page.
If you have any questions or special circumstances, our team is happy to advise before your appointment.