The invention provides apparatus and methods of preparation of lipoproteins from a biological sample, including HDL, LDL, Lp(a), IDL, and VLDL, for diagnostic purposes utilizing differential charged-particle mobility analysis methods. Further provided are methods for analyzing the size distribution of lipoproteins by differential charged-particle mobility, which lipoproteins are prepared by methods of the invention. Further provided are methods for assessing lipid-related health risk, cardiovascular condition, risk of cardiovascular disease, and responsiveness to a therapeutic intervention, which methods utilize lipoprotein size distributions determined by methods of the invention.