 The main objective is the estimation of the pooled within-patient SDs standard deviation for single treatment Adimea and of urea kinetic modeling UKM blood spKtV. Failure of KtV1.2 delivery as well as its potential causes will be assessed. spKtV target achievement is assessed by monitoring dose by Adimea at every dialysis. This shall demonstrate that session-to-session variability can be decreased with usage of Adimea. 