From the introduction of Troponin T, it was seen that patients with severe renal dysfunction had elevations of Troponin T, as compared to the use of Troponin I where this signal was not found consistently.
In the beginning, this was said to be a false positive result and that troponin is not useful among patients with severe renal dysfunction. Later, it became evident that troponin was associated with cardiovascular risks, particularly death, and there was a rethinking process – a paradigm shift that led to a clearance by FDA in the year 2004 for troponin, not only as an aid in the diagnosis of infarct in renal patients but also as a prognostic aid.
Second, “false positive” is a term that should be avoided and it’s only restricted for the true analytically false positive patients that make only a very, very small fraction of all measurements. And troponin is only the indicator of the cardiovascular disease burden and should be regarded as prognostic tools and indicators of myocardial injury.
Therefore, I would not use the term “false positives”, but the term “analytically true positives” that deserve intensified workup for identification of possible reasons for troponin release and specific treatment. The studies that have validated the fast protocols, including 0 and 1, 0 and 2, and even 3 hours, patients with haemodialysis or severe kidney disease in stage 5 were excluded from enrolment in this trial.
Therefore, we have limited experience on these patients, and we should not apply fast protocols in patients on haemodialysis or severe kidney disease. I would recommend in such cases to have the most conservative strategy, and that is admission value and repetition of the sampling at 6 hours.
And the concentration change criterion is here – an elevation from baseline by 20%, and this recommendation is based from an IFCC recommendation on patients with chronic kidney disease, where, before even using the conventional troponin, a mild elevation of troponin was seen and where it was decided to have decision above 3 times the concentration at which troponin could be measured with appropriate precision, and that is 20%. 20% increase is diagnostic for a relevant rise.
