We find that it is possible to use a sparse data set, consisting of as few as three data points per fluid, and produce a quantitative description of both pure component and blend behavior. Making use of isothermal compressibilities (kappa(T)) and thermal expansion coefficient data (alpha(P)) for a variety of polymer fluids, as well as experimentally determined critical temperatures for several blends, we apply the lattice Born-Green-Yvon (BGY) theory to the analysis and characterization of polymeric fluids and blends. In particular, we focus on polystyrene (PS), poly(vinyl methyl ether) (PVME), polybutadiene (PB), and poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) as well as the mixtures PS/PVME, PS/PB, and PS/PPO. In the first section of the paper we use the analytic expressions derived from the lattice BGY theory to analyze experimental data for the two mechanical coefficients. In the second portion of the paper we investigate the accuracy and consistency of the predictions made with each set of characteristic parameters.