There are various cut offs used for TnT and TnI reporting. The following aucomms are added to our TnI reports (Advia Centaur TnI ultra assay) using the manufacturer's recommendations:
< 0.05 ug/L No obvious myocardial damage.
0.05 – 0.78 ug/L Myocardial damage consistent with acute coronary syndrome and/or NSTEMI
> 0.78 ug/L Myocardial damage consistent with acute MI (WHO criteria)
Always interpret TnI results within the clinical context and ECG findings.
Above comments apply to samples taken 12h post-event.
All these comments are designed to enlighten the user about how to interpret the TnI test result, however it seems that a lot of patients with positive TnI results are labelled as acute MI despite the absence of other criteria to diagnose myocardial ischaemia.
How do other people report their Troponin results?
Is there a better way of reporting lab tests using test's sensitivity/specificity and positive/negative predictive values, rather than just reporting a numerical result with a reference range of dubious origin?
Many thanks
Mohammad
________________________________
From: Mohammad Al-Jubouri <[log in to unmask]>
To: [log in to unmask]
Sent: Monday, 1 December, 2008 15:54:04
Subject: Re: Troponin I - quoted cut-off value 0.10 ug/L
Richard,
We actually use 0.05 ug/L as the cut off for detecting myocardial damage (not classical MI cut off) on the Advia Centaur TnI ultra assay. As myocardial damage can be of varying aetiology ischaemic & non-ischaemic, we leave it to the clinicians to decide if the myocardial damage is due to acute coronary ischaemia or due to some other causes.
David's original statement is probably related to a recent NEQAS interpretative comment.
Best wishes
Mohammad
________________________________
From: Mainwaring-Burton Richard (RGZ) <[log in to unmask]>
To: [log in to unmask]
Sent: Monday, 1 December, 2008 15:34:36
Subject: Re: Troponin I - quoted cut-off value 0.10 ug/L
THAT IS WRONG !!!
0.1 is the M.I. cutoff for TnT and NOT TnI !
I suspect that the 0.1 value may be the lowest claimed detectable for TnI
Read ALL the small print, not just the box.
I never trust what it says on the box : I keep seeing "Open Other End " - and it never is !
with best wishes
Richard
Richard Mainwaring-Burton
Consultant Biochemist
Queen Mary's Hospital
Sidcup, Kent
020-8308-3084
-----Original Message-----
From: Mohammad Al-Jubouri[mailto:[log in to unmask]]
Sent: 01 December 2008 15:05
To: [log in to unmask]
Subject: Re: Troponin I - quoted cut-off value 0.10 ug/L
I interpret it as any TnI value of 0.1 ug/L and above indicates myocardial damage, and any value < 0.1 ug/L does not indicate myocardial damage.
regards
Mohammad
Dr. M A Al-Jubouri, MB ChB, MSc, FRCP Edin, FRCPath
Consultant Chemical Pathologist
________________________________
From:David Burgess <[log in to unmask]>
To: [log in to unmask]
Sent: Monday, 1 December, 2008 14:58:32
Subject: Troponin I - quoted cut-off value 0.10 ug/L
Please - how do you interpret the phrase, "Troponin I was analysed on an
Advia Centaur: quoted cut-off value 0.10 ug/L"
Regards, David.
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