Transketolase activity was previously used as an index of thiamine status; this test is no longer available.
Prior approval of a Chemical Pathologist is required.
Samples from outside Auckland City Hospital: sample preparation must be done by the referring laboratory. Labplus will not undertake preparation of these samples.
Thiamine concentrations are not offered as a routine test. It can be measured at Christchurch Hospital laboratory if required in exceptional cases, but only after consultation with a Chemical Pathologist. Special sample preparation and transport is required. The turnaround time may be several weeks.
In New Zealand, thiamine deficiency is seen almost exclusively in patients with malabsorption due to gastrointestinal disease, eating disorders and in alcoholics. In this setting thiamine deficiency occurs in combination with multiple other vitamin deficiencies (e.g. pyridoxine, pantothenic acid, biotin, riboflavin etc.). It is rarely helpful to test blood levels of specific vitamins, as the turnaround time is slow (several weeks) and the results are poorly correlated with the clinical response to multivitamin therapy.
Specimen Collection:
This test may be vetted by a pathologist.
The clinical information for the test must be clearly written on the request form. If clinical information is not provided, or does not provide sufficient justification for the test, the test may be declined.
Declined Tests:
If a test is declined, the specimen will be held for a reasonable period (usually 3 weeks but dependant on the stability of the sample). Medical practitioners seeking approval for a declined test should email the on-call Chemical Pathologist, giving the patient's name and NHI number and the clinical justification for the test. If unable to email, call the on-call Chemical Pathologist via Lablink and identify yourself as a doctor.
Laboratory Notes:
Any queries please contact Section Leader/Technical Specialist SCP - Special Techniques.
SPECIMEN SERVICES STAFF:
Adults: 1x 5 mL Heparin whole blood
Paediatric: 1x 1.5 mL Heparin whole blood
DO NOT CENTRIFUGE
Samples from outside Auckland City Hospital:
Sample preparation must be done by the referring laboratory. LabPLUS will not undertake preparation of these samples.
ADHB Samples:
During working hours:
Hand deliver the uncentrifuged, whole blood sample and form to the Technical Specialist in Special Techniques (SCP).
After hours:
Hand deliver to Automation staff. Automation staff are to assess whether preparation needs to be performed out of hours or if the sample can wait until Special Techniques is staffed again. Specimen preparation is to be performed within 3 days of sample collection.
Note:
The ADHB paediatricians will occasionally send some trial EDTA samples for thiamine. The trial EDTA sample will be sent with the heparin (green top non-gel) tube and will be attention Chromatography (HPLC).
- Register the heparin (green top) tube with HA suffix only, and send heparin tube and copy of form to Special Techniques (SCP) and;
- Send EDTA tubes to HPLC section (SCP).
- Afterhours hand deliver samples to Automation staff.
External Samples:
External samples should be received already prepared as a haemolysate. Haemolysate must be received as a frozen aliquot. Do not pass on to Special Techniques. Follow the send away procedure for sending samples to referral laboratories and store in the CHL frozen send away box.
Specimen Transport Instructions for Referring Laboratories:
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.
11. Transport the haemolysate with the request form at -20°C to LabPLUS.
Samples from outside Auckland City Hospital:
Sample preparation must be done by the referring laboratory. LabPLUS will not undertake preparation of these samples.