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Test Code TDP Thiamine (Vitamin B1), Whole Blood

Important Note

  • Thiamine can be collected at all sites. It will be frozen as soon as possible after it reaches Specimen Processing.
  • Patient must be fasting 12-24 hours
  • Must invert the collection tube 8-10 times
  • PROTECT FROM LIGHT/ must freeze immediately.
  • Place a notice on the orange Courier box: "Specimen for Immediate Freezing Inside"
  •  (Processors: Specimen should be frozen immediately upon receipt in the Lab. Be sure to mix well before placing in the freezer)

Useful For

Assessment of thiamine deficiency

 

Measuring thiamine levels in patients with behavioral changes, eye signs, gait disturbances, delirium, and encephalopathy; or in patients with questionable nutritional status, especially those who appear at risk and who also are being given insulin for hyperglycemia

Method Name

Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

Reporting Name

Thiamin (Vitamin B1), WB

Specimen Type

Whole Blood EDTA


Shipping Instructions


Ship specimen in amber vial or tube to protect from light.



Specimen Required


Patient Preparation:

1. Fasting: 12 hours, required; Infants should have specimen collected before next feeding, water can be taken as needed

2. For 12 hours before specimen collection, patient should not take vitamin supplements.

Supplies: Amber Frosted Tube, 5 mL (T915)

Collection Container/Tube: Lavender top (EDTA)

Submission Container/Tube: Amber vial

Specimen Volume: 4 mL

Collection Instructions:

1. Invert 8 to 10 times to mix whole blood.

2. Transfer whole blood into amber vial or tube and freeze within 24 hours of collection.


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Whole Blood EDTA Frozen 28 days LIGHT PROTECTED

Reference Values

70-180 nmol/L

Interpretation

Values for thiamine diphosphate of less than 70 nmol/L are suggestive of thiamine deficiency.

Clinical Reference

1. National Institute of Mental Health. Thiamin-Fact Sheet for Health Professionals. U.S. Department of Health and Human Services, National Institutes of Health. 2023. Updated February 9,2023. Accessed September 17,2025. Available at https://ods.od.nih.gov/factsheets/Thiamin-HealthProfessional/

2. Sodi R, Taylor A. Vitamins and trace elements In: Rifai N, Horvath AR, Wittwer CT, eds. Tietz Fundamentals of Clinical Chemistry and Molecular Diagnostics. 8th ed. Elsevier; 2020:466-487

3. Lu J, Frank EL. Rapid HPLC measurement of thiamine and its phosphate esters in whole blood. Clin Chem. 2008;54(5):901-906. doi:10.1373/clinchem.2007.099077

4. Mrowicka M, Mrowicki J, Dragan G, Majsterek I. The importance of thiamine (vitamin B1) in humans. Biosci Rep. 2023;43(10):BSR20230374. doi:10.1042/BSR20230374

5.Harper C. Thiamine (vitamin B1) deficiency and associated brain damage is still common throughout the world and prevention is simple and safe! Eur J Neurol. 2006;13(10):1078-82. doi:10.1111/j.1468-1331.2006.01530.x

Day(s) Performed

Monday through Friday

Report Available

3 to 6 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

84425

LOINC Code Information

Test ID Test Order Name Order LOINC Value
TDP Thiamin (Vitamin B1), WB 32554-8

 

Result ID Test Result Name Result LOINC Value
85753 Thiamin (Vitamin B1), WB 32554-8

Forms

If not ordering electronically, complete, print, and send a General Request (T239) with the specimen.