Simple analytical expressions for the charge density of two-electron atomic systems are studied using quantities which are of much interest in the Kohn-Sham formalism of density functional theory. Through the analysis of these quantities the overall performance of such densities can be discussed on a much firmer basis. A recent approximation to T-c[rho], the kinetic contribution to the exchange-correlation energy in density functional theory, has also been tested on these systems. It is concluded that a very high degree of quality, not only in the charge density but also in its derivatives, is needed to provide meaningful results for density functional theory quantities.