Intrinsic membrane resistance:

The other parameter, namely, intrinsic membrane resistance (R_M) is also described in dialysis procedure.

R_M   = ?x /KD_M

R_M value is characteristic of a particular membrane-solute system. The diffusive solute flux is written in terms of resistance values as below.

J_D   = ?C/R_M

Solutions adjacent to membrane surfaces are rarely well mixed and the resistance to diffusive transport resides not just in the membrane but also in the fluid regions, termed stagnant boundary layers on both the dialysate and feed side. These stagnant boundary layers offer additional resistance to diffusive solute flux and the overall resistance (R₀) is the sum of all the resistances in series.

R₀ =   R_B +R_M + R_D

where, R_B and R_D refer to resistances offered through feed and dialysate side boundary layers.