ARUP's Laboratory Test Directory

0080389: Vitamin B1 (Thiamine), Plasma

Test Mnemonic: VIT B1 P
Methodology: High Performance Liquid Chromatography

Performed: Mon-Sat

Reported: 2-5 days

Specimen Required:  
Collect: One 7 mL green (sodium or lithium heparin) or two 5 mL lavender (EDTA) or pink (K2 EDTA).

Transport: 3 mL plasma, frozen. (Min: 0.5 mL)  Submit specimen in an ARUP Amber Transport Tube.  Protect from light during collection, storage, and shipment.

Pediatric Collection/Transport: 0.3 mL plasma, frozen.  Protect from light during collection, storage, and shipment.

Remarks: CRITICAL FROZEN. Separate specimens must be submitted when multiple tests are ordered. Protect from light during collection, storage, and shipment.  Separate plasma from cells ASAP. Whole blood is preferred over plasma, which is more light sensitive.  Refer to Vitamin B1 (Thiamine), Whole Blood (0080388).

Unacceptable Conditions: Nonfrozen specimens.  Specimens not protected from light.

Stability: After separation from cells: Ambient: Unacceptable; Refrigerated: 4 hours; Frozen: 6 months (-20°C)

Reference Interval:
8-30 nmol/L

Interpretive Data:
Total thiamine, measured as thiamine (vitamin B1) and thiamine monophosphate, is reported. However, the biologically active form of the vitamin, thiamine diphosphate (TDP), is best measured in whole blood, and is not found in measurable concentration in plasma. Plasma thiamine concentration reflects recent intake rather than body stores.



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

CPT Code(s):
84425