Who is kidding whom! 551 pmol/L!!With imprecision probably
around 10% should not the instruction be to dilute anything
between 400 pmol/L and 500 pmol/L. It really is time that
clinical biochemists were honest about the inability of
automated analysers to measure these steroids in direct
assays with any measure of confidence!!!
Michael J. Diver
On Sat, 18 Nov 2000 12:11:43 -0000 [log in to unmask]
wrote:
> Hello
>
> I can confirm from a recent survey that whereas most users of
> Axsym for E2 in the UK NEQAS are employing the dilution
> protocol, a number are unhappy with their IQC and/or EQA.
>
> There is evidence in scheme data that within-method group CVs for
> a number of pools have increased comparing the most recent five
> months with the previous five months.
>
> I have seen Graham's data and would be happy to collate similar
> data from other laboratories on a confidential basis and present
> these findings to Abbott along with the UK NEQAS data.
>
> I can email some Excel plots to interested parties on request but
> will not attach them to a message to this list.
>
> I will publish summary material in due course to the Scheme
> Extras area of our website in pdf format for download by web-
> enabled participants. I can also provide laboratory-specific
> information to each participants confidential area of our web. Look
> out for this some time next week.
>
> I would advise laboratories that should they decide not to employ
> the recommended dilution protocol, they should very carefully
> validate and document this decision to avoid possible problems
> with not following the manufacturer's recommended protocol should
> there be litigation.
>
> I would encourage Abbott proactively to survey all their customers
> and provide additional reagents to enable users to assess their
> performance for clinical samples over the concentration range with
> and without the dilution step. I will make available additional UK
> NEQAS specimens to participants (subject to availability) if this
> would be helpful.
>
> I would be happy to collate data for Abbott but can only do this for
> UK NEQAS participants.
>
> regards to all
>
> Jonathan Middle
>
>
>
>
>
>
> Date sent: Fri, 17 Nov 2000 17:28:30 -0000
> Subject: Abbott AxSym Oestradiol
> From: "Ellis, Graham" <[log in to unmask]>
> To: [log in to unmask]
> Copies to: "[log in to unmask]" <[log in to unmask]>
> Send reply to: "Ellis, Graham" <[log in to unmask]>
>
> > We adopted the advice of Abbott to run AxSym oestradiols on a 1 in 5
> > dilution, repeating those <551pmol/L neat (as described in device
> > correction B7A639, July 2000). We assayed controls neat, as instructed.
> >
> > Recent poor external QC performance (with many samples run on dilution)
> > prompted a brief review of this practice. This seems to show: a)very poor
> > precision for diluted samples and b)often significantly higher results on
> > diluted samples (compared to neat.)
> >
> > Has anyone else done similar checks and what was found? It could be just
> > our Instrument, if others have good results. Please reply to me directly,
> > or to the mailbase.
> >
> > Thanks
> > Graham Ellis
> >
> >
> > St. John's Hospital
> > Livingston
> > West Lothian
> > Scotland
> > 01506 422756
>
>
> Jonathan Middle PhD
> Organiser UK NEQAS for Steroid Hormones
> Chairman UK NEQAS Executive
> Deputy Director UK NEQAS (Birmingham)
> UK NEQAS PO Box 3909 Birmingham B15 3NY
> tel 0121 414 7300, fax 0121 414 1179
> [log in to unmask] http://www.ukneqas.org.uk
----------------------
[log in to unmask]
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|