Ordering Recommendation

Do not use for evaluation of thiamine sufficiency. Refer to Vitamin B1 (Thiamine), Whole Blood (0080388) for nutritional assessment of thiamine.

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation

Green (sodium or lithium heparin), lavender (EDTA), plasma separator tube, or pink (K2 EDTA).

Specimen Preparation

Separate plasma from cells within one hour of collection. Transfer 1 mL plasma to an ARUP Standard Transport Tube. (Min: 0.2 mL)

Storage/Transport Temperature

Frozen. Separate specimens must be submitted when multiple tests are ordered.

Unacceptable Conditions

Hemolyzed specimens or specimens other than heparin or EDTA plasma.


After separation from cells: Ambient: Unacceptable; Refrigerated: 1 week; Frozen at -20°C: 6 months


Quantitative High Performance Liquid Chromatography (HPLC)




2-4 days

Reference Interval

4-15 nmol/L

Interpretive Data

Thiamine (vitamin B1) is reported. However, thiamine diphosphate (TDP), the biologically active form of thiamine, is not found in measurable concentrations in plasma, and is best determined in whole blood specimens. Plasma thiamine concentration reflects recent intake rather than body stores.

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Compliance Category

Laboratory Developed Test (LDT)


Whole blood is the preferred specimen for thiamine assessment. Approximately 80 percent of thiamine present in whole blood is found in red blood cells. Refer to Vitamin B1 (Thiamine), Whole Blood (0080388).

Hotline History


CPT Codes



Component Test Code* Component Chart Name LOINC
0080389 Vitamin B1, Plasma 20468-5
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • B1 Vitamin
  • Thiamine
  • Vitamin B1 (Thiamine),
  • VITB1
Vitamin B1 (Thiamine), Plasma