Date sent: Thu, 2 May 2002 09:11:06 +0100
Send reply to: Eric Kilpatrick <[log in to unmask]>
From: Eric Kilpatrick <[log in to unmask]>
Subject: Re: ALT reference ranges
To: [log in to unmask]
Eric,
All depends on your reference population: normal, usual or ideal?
Pat
> Brian
>
> I posted a similar question a few months ago because we had traditionally
> stated 36U/L as the upper limit for ALT, but when an academic colleague gave
> us 'normal' data from patients randomly selected from GP lists the 97.5th
> centile was 53 (Beckman LX20). Because of the skewed (long tail) data it
> meant that the 95th centile was considerably lower at 43.
>
> So where to set it? Our gastroenterologists were divided, but all agreed 36
> was too low. However some felt 53 would miss many patients with pathology,
> especially NASH. We therefore settled on 45, not as the upper limit of the
> reference range, but as an 'action limit' for clinicians.
>
> Which raises the point of whether we should quote reference ranges or action
> limits. It seems obvious that some of the rise in ALT is due to the fact
> that we are heavier and drink more than our ancestors. But we still define
> obesity as >30kg/m2 even though the 'reference interval' continues to rise
> in the population. So, when pathology and normality can overlap
> significantly, is it appropriate to quote the reference interval?
>
> I guess I'll have a good time justifying our decision when CPA next come
> round!
>
> Eric
> Dr. Eric S. Kilpatrick
> Consultant in Chemical Pathology
> Hull Royal Infirmary
> Anlaby Rd
> Hull HU3 2JZ
> Tel: 01482-607708
> Fax: 01482-607725
> ----- Original Message -----
> From: Martin Brian (RH8) R D and Exeter HC Tr
> <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Wednesday, May 01, 2002 4:05 PM
> Subject: ALT reference ranges
>
>
> > Taking the opportunity of a major change in laboratory analyser (Vitros
> 950
> > --> Roche Modular) we have swapped our main liver function test
> transaminase
> > from AST to ALT. With only a very small correlation to go on with our
> > previous method, we decided to adopt the manufacturer's suggested
> reference
> > ranges as our 'norm' (Females 5 - 31, Males 12 - 41 U/L). These are
> > identical or very close to those quoted by neighbouring laboratories.
> > However, following the change, we have noted a substantial number of
> mildly
> > elevated ALT resuts in adult patients with otherwise normal LFTs. (This
> was
> > not evident when AST was the measured transaminase). Are our ranges
> wrong?
> > Or is the ALT indicating a local population of patients with mild liver
> > damage ('retired, but drinks a lot')?. Any comments would be gratefully
> > received.
> >
> > Brian Martin
> >
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Dr. Pat Twomey,
Department of Clinical Biochemistry,
Royal Infirmary, Edinburgh EH3 9YW.
tel: 0131-5362704
fax: 0131-5362758
------ACB discussion List Information--------
This is an open discussion list for the academic and clinical
community working in clinical biochemistry.
Please note, archived messages are public and can be viewed
via the internet. Views expressed are those of the individual and
they are responsible for all message content.
ACB Web Site
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