Solutions, dialysates, and methods for measuring solutes in blood and/or for treating blood. In one aspect of the invention, a method of performing dialysis includes placing a solution in communication with blood of a subject, where a concentration of at least one electrically conductive solute in the solution, prior to being placed in communication with the blood of the subject, is substantially equal to a concentration of the at least one electrically conductive solute in the blood of the subject.