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24-Hour Vitamin B1 (Thiamine) Intake Measurement

Published: August 9, 2026Updated: August 16, 2026

This test measures how much thiamine (vitamin B1) you consumed over a 24-hour period, helping assess dietary intake and potential deficiencies.

Quick summary

["Understanding your vitamin B1 intake supports overall nutrition and health."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
81928-4
Short code
Vit B1 intake 24h Measured
Synonyms
Vit B1 intake 24h Measured
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
20
Ref high
400
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
measured
CPT
82670
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Matters

Vitamin B1 is essential for proper nerve function, energy metabolism, and red blood cell production. A deficiency can lead to fatigue, nerve damage, or other health issues. This test helps determine if your diet is providing adequate vitamin B1 over a full day.

How the Test Works

Instead of measuring blood or urine levels of vitamin B1, this test evaluates your dietary intake by asking you to track and report all foods and beverages containing thiamine for 24 hours. Some labs may use a food frequency questionnaire or dietary recall to estimate intake.

What to Expect Before the Test

No special preparation is needed. You’ll be asked to keep a detailed log of everything you eat and drink, including supplements, for a full day. Bring this log to your appointment to share with your healthcare provider.

What the Results Mean

Results are typically reported as the total amount of thiamine consumed in milligrams (mg). Low intake may indicate dietary gaps, while higher intake could reflect specific dietary needs or restrictions. Your doctor will interpret results in relation to your overall health and dietary habits.

Reference range

Premenopausal: 20-400 pg/mL; Postmenopausal: <30 pg/mLN/A

Specimen: serum

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Vitamin B1 Intake Assessment

Frequently asked questions

What does a low vitamin B1 intake mean?
A low intake may signal an inadequate diet, especially if you have limited access to foods rich in thiamine like whole grains, pork, or fortified cereals. It could also indicate an increased need due to certain medical conditions or medications. Your doctor may recommend dietary adjustments or supplements if necessary.
How does this test differ from blood tests for vitamin B1?
This test focuses on intake rather than blood levels. Blood tests assess current vitamin B1 status, while this test evaluates dietary habits. Both are useful but serve different purposes—intake helps identify dietary patterns, while blood tests detect deficiencies or excesses.
Can I adjust my diet based on this test alone?
No. Results should be reviewed by your healthcare provider, who will consider your overall health, medical history, and other test results before recommending dietary changes or supplements. They may also suggest follow-up tests if needed.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy