The principle of a novel latex agglutination test based on combined results of electrophoretic mobility and particle aggregation measurements is described. Poly (styrene/alpha-tert-butoxy-omega-vinylbenzylpolyglycidol) (P(S/ PGL)) microspheres were synthesized by a one step soap-free emulsion copolymerization of styrene and alpha-tert-butoxy-omega-vinylbenzylpolyglycidol macromonomer with number average molecular weight (M) over bar (n) = 2700 (polydispersity {(M) over bar (w)}/{(M) over bar (n)} = 1.10). Particles with monomodal size distribution (number average diameter (D) over bar (n) = 220 nm) and surface fraction of polyglycidol equal to f = 0.42 mol % were obtained. Human serum albumin (HSA) was covalently bound onto the surface of P(S/PGL) microspheres activated with 1,3,5-trichlorotriazine. In a model immunodiagnostic assay for anti-HSA, in which P(S/PGL) particles with covalently bound HSA have been used, the electrophoretic mobility and aggregation of microspheres were measured simultaneously. This approach allowed detection of anti-HSA in the serum in the range of anti-HSA concentrations from 0.1 to 150 mug/mL. The highest changes in electrophoretic mobility were registered for microspheres with surface concentration of immobilized HSA equal to Gamma = 9.2 x 10(-4) g/m(2).