Vitamin B1 (Thiamine), Whole Blood

Diagnostic Use

Thiamine (vitamin B1) is an essential vitamin required for carbohydrate metabolism, brain function, and peripheral nerve myelination. Thiamine is obtained from the diet. Body stores are limited, and deficiencies can develop quickly. Approximately 80% of all chronic alcoholics are thiamine deficient due to poor nutrition. However, deficiency also can occur in individuals who are older adults, have chronic gastrointestinal problems, have marked anorexia, are on cancer treatment, or are receiving diuretic therapy.

The signs and symptoms of mild-to-moderate thiamine deficiency are nonspecific and may include poor sleep, malaise, weight loss, irritability, and confusion. Newborns breastfed from deficient mothers may develop dyspnoea and cyanosis; diarrhoea, vomiting, and aphonia may follow. Moderate deficiency can affect intellectual performance and well-being, despite a lack of apparent clinical symptoms. Severe deficiency causes congestive heart failure (wet beriberi), peripheral neuropathy (dry beriberi), Wernicke encephalopathy (a medical emergency that can progress to coma and death), and Korsakoff syndrome (an often irreversible memory loss and dementia that can follow). Rapid treatment of Wernicke encephalopathy with thiamine can prevent Korsakoff syndrome.

It appears that no conditions are directly attributable to thiamine excess and that thiamine administration is safe except in extremely rare cases of anaphylaxis from intravenous thiamine.

Department

Lipids/Trace Metals

Delphic Registration Code

TPP

Laboratory Handling

Phlebotomy

If other biochemistry is requested requiring a lithium heparin specimen, please collect a separate non gel tube for the vitamin B1.

Registration

Send prepared washed red cells from referring labs to trace metals - freezer, otherwise send dedicated lith hep tube to Specialist lab via hoist (phone 80317).

Separating

2 mL whole blood, to be sent to Specialist lab urgently, via hoist (phone 80317). After hours prepare in Separating area as per protocol below.

Test Adds

Whole blood, frozen 28 days, light protected.

Synonyms

B1
Thiamine
Thiamine Pyrophosphate
Transketolase

Turnaround Time

14 days

Test Code

3465

Specimen Type

• Whole Blood

Specimen Requirements

Tube/Container Type:

Preferred

• Lithium Heparin - Non-gel (Green Cap)

Preferred Sample Volume (ml)

5

Minimum Sample Volume (ml)

5

No of Samples Required

1

Paediatric Specimen Requirements

Tube/Container Type:

Preferred

• Lithium Heparin - Non-gel (Green Cap)

Preferred Sample Volume (ml)

1.5

Minimum Sample Volume (ml)

1.5

Aliquot Instructions

Sample Type

• Whole Blood

Minimum Volume (ml)

2

Transport to Lab

Frozen

Additional Referral/Aliquot Information

2 mL whole blood, to be sent to Specialist lab urgently, via hoist (phone 80317). After hours prepare in separating area as per protocol below.
Send frozen prepared haemolysed cells.

The red blood cells must be washed, haemolysed and frozen before they are 4 hours old (post venipuncture). Samples for analysis of thiamine are prepared by washing the red cells with isotonic 0.9% saline, preparing a red cell lysate and freezing.

METHOD
1. Centrifuge the sample at 3000 rpm for 5 minutes.
2. After centrifugation, use a pasteur pipette to remove and discard the plasma and buffy coat layer.
3. The red cells are washed by adding an equivalent volume of isotonic saline (9 g/L NaCl) and mixing thoroughly.
4. Centrifuge the sample at 3000 rpm for 5 min.
5. Label a plastic tube suitable for transport, with the patient surname and laboratory number.
6. After centrifugation, use a pasteur pipette to remove the top saline layer and 1 mm of red cells. Discard, leaving behind the washed red cells.
7. To the labelled tube, add 1 mL of washed packed red blood cells (RBC) from the middle of the washed cells.
8. Using the same pipette tip, draw up 1 mL of distilled water and add this to the cells in the labelled tube.
9. Stopper, mix thoroughly by rolling the haemolysate around the inside of the tube.
10. Place the tube inside a plastic bag and freeze.
When frozen, send to laboratory.

Interpretation

low concentrations of vitamin B1 are suggestive of deficiency.

Reference Intervals

Recommended Range >140 nmol/L

Test Method

HPLC following production of fluorescent product.

Non-Funded Test Cost

$78.76 (Exclusive of GST)

Billing Code

3465

Contact Information

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Contact Information

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