An apparatus for extracorporeal blood treatment comprises a control unit (100) which, during the extracorporeal blood treatment, is programmed for: computing a mass balance rate (Jsoln) of a selected solute or solutes from a solute concentration (Csoln) in dialysis fluid and/or infusion fluids, from a patient solute concentration (Cpsoln), from a fluid flow rate or rates (Qpbp, Qpre, Qpost, Qdial, Qanc) and from a filtration flow rate (Qfil) or a patient fluid removal rate (Qpfr); computing, from the computed mass balance rate (Jsoln) and from a specific energy load (Emetsoln) of each solute, an energy balance (Esoln) due to the selected solute or solutes.
