Sensitive CRP assays can only discriminate between those with and without
active atherosclerosis when there are couple of hundred subjects in each
group. Sensitive CRP measurements can't confidently discriminate between
individuals. Our calculations indicate that the number of samples required
from an individual to obtain a clinically useful estimate of their true
hs-CRP concentration lies between 10 and 50. See our Ann Clin Biochem
paper referenced below and the other articles as well which give more
reasons why hs-CRP is not clinically useful.
Ridker has suggested that we could just do a number of measurements over
time and pick the lowest value. However there are a number of untested
assumptions inherent in this idea that would need to be validated. The
experiments required to identify and quantify the factors which contribute
to both minor and major variation in plasma CRP concentrations are not
going to be easy to perform. We are setting up a study to follow subjects
over time while they record a health diary to see whether clinically
significant intra-individual variations in hs-CRP are subjectively or
objectively identifiable. It is our hypothesis that many such variations
will be silent.
Campbell B et al. Limited clinical utility of high-sensitivity plasma
C-reactive protein assays. Ann Clin Biochem 2002;39:85-88
Kushner I. C-reactive protein and atherosclerosis. Science 2002;297:520-21
Kushner I, Sehgal AR. Is high-sensitivity C-reactive protein an effective
screening test for cardiovascular risk? Arch Int Med 2002;162:867-9
Levinson SS, Elin RJ. What is C-reactive protein telling us about coronary
artery disease? Arch Int Med 2002;162:389-95
Bruce Campbell
****************************************
Bruce Campbell FRCPA FAACB
Sullivan Nicolaides Pathology
Ph 61 (0)7 3377 8672
Fax 61 (0)7 3870 5989
Email [log in to unmask]
****************************************
Craig Webster
<[log in to unmask]> To: [log in to unmask]
Sent by: clinical cc:
biochemistry discussion Subject: Re: sensitive CRP and CHD
list
<ACB-CLIN-CHEM-GEN@JISCM
AIL.AC.UK>
21/01/03 04:28
Please respond to Craig
Webster
Sensitive CRP was mentioned in a Plenary Lecture by Matt McQueen at the
ICCC
kyoto. Within individual variation data suggests that up to 5 measurements
of sensitive CRP may be neccessary to obtain a value that can be used in
the
assessment of CHD risk. WHich is probably even better news for
manufacturers!
The theory that atherlosclerosis is a chronic low grade inflammatory
reaction underpins its measurement.
I always thought that CRP was probably under requested in the past due to
long turn around times etc. Now that we can turn the test around quickly
surely we are seeing the benefits of all our execellent work on improving
the service we provide :-)
Craig Webster
Principal Clinical Biochemist
Nottingham City Hospital
-----Original Message-----
From: clinical biochemistry discussion list
[mailto:[log in to unmask]]On Behalf Of David Brown
Sent: 20 January 2003 17:25
To: [log in to unmask]
Subject: Re: [ACB-CLIN-CHEM-GEN] sensitive CRP and CHD
Like everything else, apparently, new "sensitive" CRP
is the same non specific CRP we have been measuring
for years, only it is more sensitive in the lower
range. There is sufficient interest in this assay as a
cardiac risk factor, that there is more than one assay
method on the market. My experience of assaying CRP's
consisted of seeing - most below measurable range -
and the rest so sky high, that I wondered if the test
was really necessary (but that was a few years ago).
Now I may be led to believe that it is as valuable as
measuring a total cholesterol. There are several major
studies indicating this. For those who are
interested,this web page explains sensitive CRP (from
a manufacturers point of view) and gives some
references too.
http://www.sonoraquest.com/documents/CardioCRP.pdf
Best wishes
David Brown
--- "Mainwaring-Burton Richard (RGZ)"
<[log in to unmask]>
wrote: > In the light of the significant numbers of
raised
> (non-sensitive) CRPs we
> report for a plethora of reasons, how do we pick out
> the significant
> elevations of sensitive CRP ?
>
> Suggested stratigies :
> 1. do a low sensitivity assay first
> 2. apologise to potential CHD patients with
> high CRP - test no good
> until arthritis/crohns/flu/etc cleared up
> 3. wait for the cardio-specific version ?
>
> With best wishes - happy new year
> Richard
> Biochemistry Department
> Queen Mary's Hospital
> Sidcup, Kent
> DA14 6LT
>
>
>
> -----Original Message-----
> From: Paul Collinson
> [mailto:[log in to unmask]]
> Sent: Tuesday, January 14, 2003 21:07
> To: [log in to unmask]
> Subject: Re: sensetive CRP
>
>
> In message <[log in to unmask]>,
> Dr Clara Henig
> <[log in to unmask]> writes
> >Dear all
> >
> >What do you know about the utilities of sensitive
> CRP as a CHD marker?
> >Does anyone use it routinely? What are your
> recommendations?
> >
> >Thanks
> >Clara
> >
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> There have been a number of publications by Paul
> Ridker
>
> We use it routinely for priomary risk stratification
> with the cut-off for
> low
> risk <1, inetremediate 1-3 and high risk >3 (mg/L)
>
> --
> Paul Collinson
>
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Please note, archived messages are public and can be viewed
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