It can be very difficult to separate out smokers from urban dwellers. As
suggested elsewhere, expired CO levels are a better marker of smoking.
We did look at the microplate assay from Cozart for detecting passive
smoking in children, but it was not sensitive enough.
David G Williams
Dr Pat Twomey wrote:
>
> >From memory, I believe that nicotine has a short half life (circa 30
> minutes) while cotinine has a much longer half life (circa 18 hours) -
> thus the reason why we measure cotinine and not nicotine.
> Thus, any source (recent or otherwise) of nicotine would produce
> cotinine. It is also important to note that nicotinic acid can also
> cause problems as can high levels of passive smoking (partners,
> housemates, social life). Perhaps a carbon monoxide level may
> help (even on a venous sample) but urban/rural factors should be
> taken into account.
>
> Pat
>
> Cotinine is the major metabolite of nicotine. I think that
> it is
> unlikely that nicotine patches would contain cotinine,
> ergo, the
> presence of cotinine in the sample indicates recent
> smoking.
>
> David G Williams
>
> Dr Pat Twomey wrote:
> >
> > I can't see why nicotine from a patch should be any different from
> > nicotine obtained from a cigarette and thus would expect a
> positive
> > result. The question really is what levels do you achieve with
> > patches and other forms of Nicotine Replacement Therapy and I
> > can only assume that they should be similar to smoking if they
> > were to have a pharmacological effect. You do not correct for
> > creatinine which may make interpretation more difficult. But even
> > this would not help if Nicotine Replacement Therapy achieves
> > pharmacological levels of nicotine/levels comparable to smoking.
> >
> > Pat
> >
> > Date sent: Mon, 17 Jan 2000 17:25:38 -0000
> > Subject: Urine cotinine
> > From: Moran Louise
> > <[log in to unmask]>
> > To: "Acblist (E-mail)" <acb-clin-chem-
> > [log in to unmask]>
> > Send reply to: Moran Louise
> > <[log in to unmask]>
> >
> > We have a lady who is scheduled for lung volume reduction
> surgery
> > in a few
> > weeks time and says she gave up smoking on Christmas Day,
> but
> > since then has
> > been using nicotine patches. The Registrar requested a urine
> > cotinine which
> > was positive (>500 ng/mL - Cozart Biosciences). Does anyone
> > have any
> > experience of interpreting urine cotinine results when the patient
> > reports
> > using nicotine patches? I'm afraid I don't know what type of
> patches
> > she is
> > using or the dose.
> >
> > Thanks for your help
> >
> > Louise Moran
> >
> > Louise Moran
> > Senior Clinical Scientist
> > Dept of Clinical Biochemistry
> > Royal Brompton & Harefield NHS Trust
> > Sydney St
> > LONDON SW3 6NP
> > 0171 351 8418 (Fax 0171 351 8416)
> > Bleep 0171 352 8121 (No 7365)
> > [log in to unmask]
> >
> > Dr. Pat Twomey
> > Department of Clinical Biochemistry,
> > Royal Infirmary, Edinburgh.
> > tel: 0131-5362704
> > fax: 0131-5362758
>
> --
> David G Williams
> Department of Biochemistry
> Sunderland Royal Hospital
> [log in to unmask]
>
> Dr. Pat Twomey,
> Department of Clinical Biochemistry,
> Royal Infirmary, Edinburgh EH3 9YW.
> tel: 0131-5362704
> fax: 0131-5362758
--
David G Williams
Department of Biochemistry
Sunderland Royal Hospital
[log in to unmask]
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|