Intra-individual variability in troponin T concentration in dialysis patients

Purpose: Haemodialysis patients often have increased TnT concentrations in the absence of symptoms suggestive of acute coronary syndrome. To evaluate the potential usefulness of establishing patient specific baselines, we investigated intra-individual variability of TnT concentration in stable haemodialysis patients. Methods: We measured pre-dialysis troponin T concentrations weekly for 15 weeks in 61 stable haemodialysis patients. Results: Thirty two of 61 patients had at least one result greater than the diagnostic cut-off for significant myocardial damage of 0.04 mu g/L. The intra-individual variability was small; 99% of all the variance from each patient's median was <= 0.063 mu g/L. Conclusions: Intra-individual variability in TnT concentration is small enough to merit establishment a of baseline concentration for each haemodialysis patient. This baseline is stable over at least 15 weeks; samples need be collected no more frequently than this. A change in concentration of more than 0.06 mu g/L from the individual's baseline is significant. (c) 2009 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.