22 Cardiac troponin T is frequently elevated when repeatedly measured over time in patients receiving dialysis. After five cTnT levels were measured every 3 months over a 12 month period, cTnT was normal in all five samples in 35% of patients, elevated in some but not all samples in 24%, and elevated in all five samples in 41% of patients.24 This ‘bimodal’ distribution of serial cTnT has also been demonstrated by other investigators25,26 and confirms that a significant proportion of patients

undergoing dialysis have either an elevated or a normal cTnT concentration every time it is measured. Serial cTnT measures correlate strongly within individuals,27 and where the within individual Ferroptosis inhibitor drugs variation has been measured in weekly samples, 95% of the variance from the median value was ≤0.021 µg/L, and 99% of this variance was ≤0.06 µg/L, suggesting see more that a rise of cTnT

by these amounts should be interpreted as clinically significant.25 One study has demonstrated that 72%, 15% and 14% of dialysis patients, respectively, had zero, one to four and all five cTnI levels elevated over a 12 month period,28 suggesting a very different distribution of serial cTnI levels to cTnT. Studies of the effect of the dialysis procedure on cardiac troponin levels are limited by variability between assays and variable correction for haemoconcentration. Accepting these limitations, cTnI either decreases29,30 or does not change31–36 after haemodialysis, whereas cTnT either increases30,34,37,38 or does not change.27,31,32,35 However, one study demonstrated a fall in troponin T post dialysis,39 Dipeptidyl peptidase and cTnT was lower after dialysis only in patients using high flux dialysers.29 Troponin is thus best measured on pre-dialysis

samples unless clinical symptoms dictate otherwise. Troponin may normalize in patients after receiving a kidney transplant, but studies to date have been small and results vary with the specific assay used.40–42 In cross-sectional data, a greater proportion of patients receiving dialysis had elevated cTnT compared with patients who had received a kidney transplant.23 There is no reference range for BNP that takes account of kidney function and most patients undergoing dialysis have elevated BNP using general population reference ranges. In one study, 99% of haemodialysis patients had NT-BNP-76 levels above the reference ranges43 and in peritoneal dialysis patients, NT-BNP-76 levels were 10-fold higher than the upper limit of normal for a reference population.44 Both BNP-32 and NT-BNP-76 were significantly higher in patients receiving dialysis compared with patients with chronic kidney disease and kidney transplant recipients.5 Haemodialysis patients had significantly higher BNP-32 than patients receiving peritoneal dialysis.