Finally, one common sense contribution to the timing of troponin sampling. Today's troponin methods achieve TAT of less than 1 h. We believe that having invested in equipment for these sensitive, cardiospecific ( and expensive ) markers we should use them rationally to provide early info to our well informed cardiologists. Our 2000 study based on frequent serial sampling, led to our current routine of parallel determinations of myoglobin + troponin T ( CK MBmass is being phased out ) in serial samples: admission, 2, 6, 12, 18 h.
All determinations are done STAT, ( Elecsys 2010 ) with electronic reports within one h on a 24h, 7/7 day basis. This is achieved with serum, not heparin samples, ( Gerhardt et al. Clin Chem 2000; 46: 817-21 ). Sampling stops when the cardiologists has adequate clinical info. The lab routinely sends out cumulative graphic time curves from the following day. These graphs provide clear info in patient records..
The new lower troponin cut-offs ( Consensus criteria ) have made troponins earlier markers than before.Obviously, serial sampling may provide higher diagnostic sensitivity in very small myocardial necrosis than one or two some random samples - especially if these are not even analyzed before 6 or 12 h !
Our cardiologists have actually asked for "ultra-fast" report ( 30 minutes ) in a few cases, e. g. in LBBB in which early positive troponin T actually was decisive for treatment.
Early PTCA carried out before major myocardial necrosis has developed may lead to better life quality and, perhaps, less cost for health care for these treated patients in the long run.
As for costs, we believe these may be seen as trade-off between lab costs versus the highly expensive CCU.
Willie Gerhardt
Dept Clin Chemistry
Helsingborgs Lasarett AB
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----- Original Message -----
From: "Annus, Tibor" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, January 15, 2002 2:41 AM
Subject: Re: Troponin timings
> What is the point of taking a specimen at the time of presentation for
> analysis 6-8 hours later.? Surely the idea of taking a specimen at
> presentation is to start treatment as early as possible if the result is
> positive.
>
>
> -----Original Message-----
> From: David Parry [mailto:[log in to unmask]]
> Sent: Tuesday, 15 January 2002 0:21
> To: [log in to unmask]
> Subject: Troponin timings
>
>
> I agree with Paul Collinson (message 1/9/02) that timing depends upon prior
> probability and acceptable miss rate, but disagree with the way he has
> calculated miss rate. Missing 45 out of 50 MIs is a miss rate of 10% in my
> book, not 0.5% as was calculated based on a population tested of 1000.
>
> I am also concerned with the testing policy (of Jonathan Kay) that states
> that a second specimen at 12 hour post onset of symtoms should always be
> collected for TnI in addition to a first specimen obtained when patient is
> first seen. The concern I have with this strategy is that many of the
> patients tested (>50% in our locale) at 1 or 2 hours after presentation do
> not get another blood sample collected for TnI for a number of reasons, one
> being that the patient has been sent home. It does not seem practical to me
> to force the Emergency Dept to test again at 12h in all patients initially
> tested because a TnI was ordered on presentation, as much as we may think
> this is the right thing to do.
>
> This takes me back to the point made by Paul Collinson that a testing
> strategy should take into account timing practicality and acceptable miss
> rate. If a 10% miss rate is acceptable (as was suggested it is) and this is
> acheived at 6h post onset of symptoms, then I would suggest that the first
> specimen be collected at this time and not before. This way no patient would
> be sent home with a TnI test performed on blood collected 1 hour after
> presentation as is the case now.
>
> I can think of one other testing strategy alternative when troponin is the
> only biochemical marker available. Collect first specimen on presentation
> and again after 6-8 hours, but analyze TnI on both only when the second
> specimen is taken.
>
> I would appreciate any feedback on this.
>
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