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r=0.32 and r=0.24 respectively; P<0.001). There was extreme co-linearity between D-PVS and haemoglobin in linear regression models with other continuous variables (VIF = 14). Higher H-PVS (hazard ratio (HR) = 1.01 (95% confidence interval (CI) = 1.00 -1.02); P=0.002) or D-PVS (HR = 1.08 (95% CI = 1.03 -1.14); P=0.002) was associated with greater risk of all-cause mortality or hospitalisation with heart failure. Neither the Harrel's C-statistic nor AIC of outcome models for 1 year mortality including either weight or haemoglobin were improved by the addition of H-PVS or D-PVS (figure 2). Conclusions Changes in weight or haemoglobin in patients with CHF are not always due to changes in plasma volume. Despite apparent associations with disease severity, H-PVS and D-PVS are just surrogates of the variables from which they are calculated and not reliable measures of congestion. It is likely neither has any clinical utility.