Abstract: A method of rapidly detecting presence of antibodies in a solution comprises depositing, on each of a plurality of microscopic particles, an antigen specific to the antibodies sought, and forming a dilute suspension of the particles in the solution to be examined. The suspension is stirred, and electrophoretic mobility of the particles is measured upon formation of the suspension and measured again at a subsequent time. Detection of a change in electrophoretic mobility of the particles between the two measurements indicates presence of the antibodies in the solution.