Short- and Long-term Individual Variation in Cardiac Troponin in Patients with Stable Coronary Artery Disease

Abstract

BACKGROUND A rise or fall of cardiac troponin is a prerequisite for the diagnosis of acute myocardial infarction. Defining significant changes requires knowledge of both biological and analytical variation. The short-term biological variation of cardiac troponin in healthy individuals is 3%–48%. However, healthy individuals may not be representative for patients in whom cardiac troponin measurement is often of clinical importance. Therefore, we studied the individual variation of cardiac troponin in patients with symptoms of stable coronary artery disease. METHODS Twenty-four patients scheduled for elective coronary angiography were included. Blood samples were drawn once at enrollment and serially at six 4-h intervals on the day before coronary angiography. Cardiac troponin was measured with hs-cTn assays from Abbott Laboratories (premarket cTnI assay) and Roche Diagnostics (Elecsys® cTnT assay with two different lots). RESULTS The short-term individual variation in cardiac troponin I (cTnI) was 14%, the reference change value (RCV) 49%, and RCV-log-normal (rise/fall) 54%/−35%. The corresponding values for cTnT were 7%, 23%, and 26%/−21%. The long-term variation for cTnI was 24%, RCV 69%, and RCV-log-normal (rise/fall) 97%/−49%. The corresponding values for cTnT were 11%, 32%, and 37%/−27%. CONCLUSIONS The short-term individual variation of cardiac troponin in patients with symptoms of stable coronary artery disease is similar to the biological variation previously demonstrated in healthy individuals. Our results suggest that a change in cardiac troponin concentrations of >50% can be used in attempting to diagnose acute myocardial injury. To detect significant long-term changes in cardiac troponin concentrations, larger changes will be required.

Biological variation of high sensitivity cardiac troponin-T in stable dialysis patients: implications for clinical practice

“…The weekly and monthly within-person variation of hs-cTnT estimated from dialysis patients in this study was markedly smaller than corresponding values reported for healthy individuals (15% and 31%, respectively) [30], but similar to those reported for non-dialysis dependent individuals with coronary artery disease (7.3% at 4-hourly intervals and 10.7% at 3-weekly intervals) [31]. These findings are likely explained by the fact that both dialysis patients and non-dialysis dependent patients with coronary artery disease have baseline troponin-T concentrations around or exceeding the 99th centile upper reference limit of the hs-cTnT assay [16,31] whereas healthy individuals have much lower baseline values [11].…”

Evaluation of Temporal Changes in Cardiovascular Biomarker Concentrations Improves Risk Prediction in an Elderly Population from the Community

“…Normal biomarker concentrations without relevant increases, in contrast, might support clinicians in their decisions about not starting or even stopping medications with potentially harmful side-effects, a relevant issue in elderly populations. The appropriate timing of repeat measurements, however, remains to be determined, also taking the biologic variability of these biomarkers into account (34,35 ). For GDF-15, these recommendations are not similarly straightforward given the association of this biomarker with both CV and non-CV conditions (5,10,14,(25)(26)(27).…”

High sensitivity cardiac troponin assays in the clinical laboratories

“…Another important, measurable parameter is the inter-individual variation, which reflects biological variations among healthy individuals from a defined population. A number of investigators measured intraand inter-individual variations using various cTn assays [15,[55][56][57][58][59][60]. The results ranged from 4% to 30% for intraindividual variations and from 30% to 200% for interindividual variations as summarized by Nordenskjöld and coworkers [60].…”