Highly sensitive troponin can be used to detect myocardial infarction at 3rd hour of onset compared to 6th hour of onset on non hs troponin.
Refs:
Reichlin T, Hochholzer W, Bassetti S, Steuer S, Stelzig C, Hartwiger S, et al. Early diagnosis of myocardial infarction with sensitive cardiac troponin assays. N Engl J Med. 2009 Aug 27;361(9):858-67.
Daubert MA, Jeremias A. The utility of troponin measurement to detect myocardial infarction: review of the current findings. Vasc Health Risk Manag. 2010;6:691-9.
Firstly, my opinion is that it's not only about changing from cTnI to cTnT. Changing the platform / analyzer we are using is not so easy. Changing an automated analyzers will require huge investment. Not all laboratory had the luxury. Secondly, hs cTnI also available.
Thank you for your answer. I believe that troponin T is less specific than troponin I, so why is troponin T preferred to troponin I? Is it more sensitive? More reliable?
I read that high sensitive (hs) cTnT and hs cTnI gave similar performance.
Reichlin et al. NEJM (2009) 361: 858
In our lab, we choose cTnT because we are using Roche instruments package (automated preanalytics with MPA, clinical chemistry: Cobas c501, c311, immunology: Cobas e411/e601). To my knowledge, cTnT developed only by Roche. One advantage is that it gave a kind of harmonization across Roche instrument users internationally.
Roche service and packages in our situation is very good. So, we are not only considering about cTn, but we are considering all of our automated clinical chemistry and immunology services. The situation for other lab/countries, may differ thou.
If we have to change to cTnI, we need to buy a new autoanalyzer. Moreover, cTnI developed by several vendors. Not every cTnI package/reagents and analyzers gave the same performance.
The most important reason for the different use of the 2 troponins is of commercial type. cTnT is Roche patent only and is not available for other Companies (Abbott, Beckman Coulter or Siemens). So, cTnT is employed in the laboratories that use Roche analyzers only. The cTnI from different Companies have some analytical differences.
Troponin T is less specific than troponin I as stated in the previous answers of my colleagues, but Troponin T remains in the plasma from 7-14 days giving us a good chance for diagnosis.