The addition of pyridoxal-5-phosphate to the ALT and
AST methods is a requirement by the IFCC-enzyme panel
(Ref. Clin Chem 1978; 24: 720-1). This has been shown
to improve precision using various autoanalysers (Ref.
Clin Biocehm 1988; 21: 283-90). Reference ranges
derived by IFCC conforming methods are therefore
different from those derived by other methods not
including pyridoxal-5-phosphate. I would like to
mention an interesting observation regarding the
finding of low ALT in some patients. Despite using a
pyridoxal activated method in our laboratory, I have
been noticing a significant number of low ALT (< 6
IU/L)in various patient groups. I have always linked
this to pre-clinical vitamin B6 deficiency state. I
have noticed this in elderly patients with dementia,
psychiatric patients and obviously in malnourished
patients. Another interesting group are patients with
rheumatoid arthritis on low dose methotrexate who come
for routine LFT measurement. I am particularly
interested in the latter group and wonder whether any
of you have noticed low ALT in such patients. Of
course this may reflect a vitamin B6 deficiency state
induced by methotrexate. On a limited number of
patients in our ICU who exhibited a low ALT, I have
advised giving parenteral pabrinex emprically and this
consistently caused a rise of ALT by around 10 IU/L.
Regards.
--- June Wingert <[log in to unmask]> wrote: >
greeetings!
> anyone know what the advantage is to using the
> Pyridoxal Phosphate
> Activated medthod over the method without
> pyridoxal-5-phosphate ?
> I know that pyridoxal phosphate serves as a coenzyme
> in the amino transfer
> reaction and therefore if there is a deficiency of
> pyr than you will get no
> alt reading. but, barring the deficency are there
> any other advantages.
> thanks
> June Wingert
> Research Associate
> Lexicon Genetics
> The Woodlands, Texas
>
>
=====
Dr. M A Al-Jubouri
Consultant Chemical Pathologist
Whiston Hospital
Prescot
Merseyside L35 5DR
UK
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