In message <[log in to unmask]>, David Parry
<[log in to unmask]> writes
>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.
It is 10% of the infarcts but 0.5% of the chest pains - and currently 5% of
chest pain sent home has had an AMI
--
Paul Collinson
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