We tried to do the same, but our 917 / CEDIA results did not match the
results from the reference lab we usually send it to. We were told by
Roche that their CEDIA method did not work for free phenytoin. It didn't
make sense to me that it shouldn't but we didn't pursue it any further as
we don't get enough requests.
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Wolfgang Schneider
Division of Medical Biochemistry, Montreal General Hospital
1650 Cedar Avenue, Montreal, Quebec H3G 1A4, Canada
Phone (514)-937-6011 x 2782 Fax (514) 934-8086
Email at work: [log in to unmask]
Email at home: [log in to unmask]
Manufactured only with 100% recyclable electrons
***********************************************************
>> We measure free phenytoin by making an ultrafiltrate of serum using an
> > Amicon filter (Centrifree YM-30) and measuring phenytoin in the
> > ultrafiltrate using our usual phenytoin method on a Roche 917. We have
> > had complaints that the results are too high and this seems to be true
> > (we don't do many) because the free is a substantial proportion of the
> > total (? 30 - 105%). However, the protein content of the ulrafiltrate
> > is appropriately low (0 - 1 g/L) so the membrane seems to be excluding
> > the protein OK.
> >
> > Has anyone else had similar experiences? Any suggestions?
> >
> > Thanks
> >
> > John Whitfield
> > Clinical Biochemistry
> > Royal Prince Alfred Hospital
> > Sydney.
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