Laboratory Services

Thiamine (Vitamin B1), Whole Blood

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Updated Test Information:

Test Description
Thiamine (Vitamin B1), Whole Blood

Thiamin Diphosphate (TDP); Thiamin Pyrophosphate (TPP); Thiamine; Vitamin B1; VITB1; B1, Vitamin

Test ID
General Information

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

  • Whole blood thiamine testing is superior to currently available alternative tests for assessing thiamine status. Serum or plasma thiamine testing suffers from poor sensitivity and specificity, and less than 10% of blood thiamine is contained in plasma

  • Thiamine diphosphate (TDP) is the active form of thiamine and is most appropriately measured to assess thiamine status. Thiamine diphosphate in circulating blood is present in erythrocytes, but is undetectable (present in very low levels) in plasma or serum

  • LC-MS/MS analysis of TDP in whole blood is the most sensitive, specific, and precise method for determining the nutritional status of thiamine and is a reliable indicator of total body stores

  • This assay specifically targets and quantitates the active form of thiamine, TDP, as an indicator of thiamine status


Specimen Type

EDTA Whole Blood

Specimen Requirements

Lavender Top (EDTA)

Specimen Collection / Processing Instructions

  • Patient Preparation:

    • Fasting overnight (12-14 hours)

    • Infants-draw prior to next feeding

    • Water can be taken as needed.

  • Invert 8 to 10 times to mix blood

  • Transfer whole blood into amber tube

    • Specimen must be frozen within 24 hours of collection.

Minimum Sample Volume

0.5 mL

Additional Processing Details

Ship specimen in amber tube to protect from light


Frozen: 28 days

Unacceptable Specimen Conditions

  • Gross lipemia

  • Glass vial

  • Clotted specimen


Vitamin supplementation and nonfasting specimens may result in elevated thiamine diphosphate concentrations


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

Estimated TAT

2-5 days

Testing Schedule



14 days

CPT Code(s)


Reference Range

70-180 nmol/L

Performing Lab


LOINC Code(s)


Additional Information