Thiamine (Vitamin B1), Whole Blood
Use
This test is used for the assessment of thiamine deficiency, especially in patients presenting with behavioral changes, eye signs, gait disturbances, delirium, encephalopathy, or questionable nutritional status. Thiamine plays a crucial role in carbohydrate metabolism, brain function, and peripheral nerve myelination. Whole blood thiamine testing is considered superior to serum or plasma testing due to better sensitivity and specificity, with the active form thiamine diphosphate (TDP) being measured as an indicator of thiamine status.
Special Instructions
Patients must fast for 12 hours before specimen collection, and infants should have specimens collected before the next feeding. Water intake is allowed, but vitamin supplements should be avoided for 12 hours prior to collection. Specimens should be shipped in amber vials to protect from light. If not ordering electronically, fill out and send a General Request form with the specimen.
Limitations
Elevated thiamine diphosphate concentrations may occur with vitamin supplementation and non-fasting specimens. The test is specifically designed to measure thiamine diphosphate and may not be suitable for assessing serum or plasma thiamine, which contains less than 10% of total blood thiamine. Transketolase activity assays are less sensitive and specific compared to this method, and other factors may influence transketolase activity, leading to potential diagnostic errors.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 32554-8
- 32554-8
Result Turnaround Time
3-6 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
4 mL
Minimum Volume
0.5 mL
Container
Lavender top (EDTA)
Collection Instructions
Invert 8 to 10 times to mix whole blood. Transfer whole blood into amber vial or tube and freeze within 24 hours of collection.
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.
Storage Instructions
Ship specimen in amber vial or tube to protect from light.
Causes for Rejection
Gross lipemia, glass vial, clotted specimen
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 28 days |