I would like to make contact with anyone measuring blood thiamine levels by
HPLC. I have a Masters student doing his project in the above area and have
only found one other laboratory in Australia which has looked at this and
they have opted for a
microbial bioassay as the HPLC method had problems - we have trialled the
Biorad thiamine assay but are not completely
happy with its performance. The method showing the greatest promise is that
published by JW Brunnekreeft et al. J Chrom 491
(1989) 89-96 - a precolumn derivatisation method using ferricyanide to
produce the thiochrome. We have kindly been given some material from SKZL
along with the EQAP results - we were intrigued that the majority of
laboratories reporting results used cyanogen bromide derivatisation - is
this for some historical reason or can it be safer to use or better
performing than ferricyanide?
Do laboratories measuring thiamine measure total thiamine by individual
quantitation of TMP,TPP,TTP and Thiamine and summation or by the
prechromatographic cleavage of the phosphate moieties to give one thiamine
peak or by just quantitating the TPP peak (80-90% of total and presumably
that fraction measured by the ETK assay)? Which sample (urine, blood,
fasting plasma) shows the best correlation with brain levels?.
The decision by Roche to discontinue supporting the Cobas Bio has led us
scrambling to our HPLC looking for an alternative
to the current ETK assay - by far the most popular method used to assess
the thiamine status in our at risk patient population
here in Australia.
Thanks
Michael Freemantle
Sullivan Nicolaides Pathology
PO Box 344
Indooroopilly Q4068
Brisbane
Australia 4068
ph +61 (0)7 33778638
fax +61 (0)7 38705989
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