Abstract: Method and apparatus for enabling resuspension wash and magnetic localization of sample components bound to particles with magnetic properties in reaction vessels during separation and wash for enhanced chemiluminescent signal generation in biomedical assays. The assays involve moving reaction vessels past magnets that partially localize the particles prior to passing a reduced strength magnet where washing occurs, with or without resuspension, after separating out the unbound particles and liquid. The band of particles is subsequently resuspended in acid for chemiluminescent purposes. A variety of magnet configurations are employed to realize the reduced strength magnet. Reduced strength magnets adjacent the full width magnets prevent the band of magnetic particles from becoming split. The localized particles enable more efficient resuspension by reagent.