If I recall correctly Fred Apple talked about this at AACC this year. If above the 99th centile that is ACS not necessarily AMI.  On-admission and 6h sampling with 12 hour if on admission not raised. Values > 0.01ng/ml for Trop T meant cardiac damage and if it wasn’t rising it was chronic. According to me the LLQ for this assay is 0.03ng/ml, but he may have a super-sensitive assay. Makes sense if we could do it?

 

Ian

 

Dr Ian D Watson

Consultant Biochemist & Toxicologist

Dept Clinical Biochemistry

University Hospital Aintree

Lower Lane

Liverpool

L9 7AL

Tel +44 151 529 3575

Fax +44 151 529 3310

 

Fundamentals of Analytical Toxicology recently published:
http://eu.wiley.com/WileyCDA/WileyTitle/productCd-0470319356.html

 

 

 

From: Clinical biochemistry discussion list [mailto:[log in to unmask]] On Behalf Of SERGEANT Chris (RF4) BHR Hospitals
Sent: 03 December 2008 10:48
To: [log in to unmask]
Subject: Re: Troponins reporting

 

We use a testing strategy that includes the possibility of repeat analysis to observe changes in troponin concentration when diagnosis is uncertain We have advised clinicians of the manufacturers quoted 99th centile cutoff as this is the concentration, according to the guidelines, consistent with AMI. As stated below, other evidence of myocardial ischaemia is important for the diagnosis, as well as a "rise and or fall".  The clinical specifity and sensitivity of the lab result is not only affected by setting the "cutoff" at the 99th centile but also the timing of the sample(s) in relation to symptoms and the reproducibility of the assay. We try to ensure clinicans do not simply see a single TNI result (often taken at varying times post symptoms) as a simple "yes" or "no" number, although this is often what they want.

 

Chris

 

-----Original Message-----
From: Clinical biochemistry discussion list [mailto:[log in to unmask]]On Behalf Of Myers Martin (LTHTR)
Sent: 03 December 2008 10:08
To: [log in to unmask]
Subject: Re: Troponins reporting

I am a little uneasy about the "AMI Cut offs" that would indicate AMI.   Are these evidence based?  What does an arbitary cut off, e.g. 0.1 for troponin T (at a fixed time point of 12 hr), actually mean and how would one interpret the following:

admission TnT = <0.01

12 hour troponin T = 0.09

 

The Expert Consensus Document, Universal Definition of Myocardial Infarction, Circulation 2007;116;2634-2653;  defines a acute myocardial infarction as (amongst others) : a rise and/or fall in [troponin] with at least one level above the 99th percentile of the URL together with evidence of myocardial ischaemia (at least one of the following: symptoms, ECG changes, pathological Q wave, imaging evidence).  There is not mention of another arbitary cut-off which would indicate AMI. 

 

martin

 

 

-----Original Message-----
From: Clinical biochemistry discussion list [mailto:[log in to unmask]]On Behalf Of Indovina, Joe [OCDUS]
Sent: 02 December 2008 18:39
To: [log in to unmask]
Subject: Re: Troponins reporting

Good discussion

 

To help I went through my files and put together a table of different vendors troponin assay cut offs and 99% URL

 

I used the package insert sheets that I have and thus urge caution as some may not be 100% current

 

What it does show is, in my opinion, the importance of identifying on the lab report as Mohammad does

 

Abbott AxSYM TnI ADV

Abbott AxSYM TnI ADV

Beckman AccuTnI

Bayer Centaur Ultra TnI

Dade RXL

DPD STAT TnI

Roche TnT

Vitros Trop I ES

 

 

 

 

 

 

 

 

 

 

 

AMI Cut-off

0.4

0.3

0.5

0.8

1.5

??

0.1

0.120

 

 

 

 

 

 

 

 

 

 

 

URL 99th Percentile

<= 0.04

0.012

<= 0.04

0.04

<= 0.05

0.2

0.01

0.034

 

 

 

 

 

 

 

 

 

 

 

units

ng/mL

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

-----Original Message-----
From: Clinical biochemistry discussion list [mailto:[log in to unmask]]On Behalf Of Mohammad Al-Jubouri
Sent: Tuesday, December 02, 2008 9:06 AM
To: [log in to unmask]
Subject: Troponins reporting

 

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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