Embodiments of the invention provide methods of preparing an activated acridinium microparticle. Generally, the methods involve direct covalent coupling or an affinity format. The direct covalent coupling method involves coating a microparticle with a proteinaceous compound. Then, a 10-methyl-N-tosyl-N-(2-carboxyethyl)-9-acridinium carboximide trifluoromethane sulfonate is coupled to the proteinaceous compound. In the affinity format, a microparticle is coated with a biotinylated proteinaceous compound. The microparticle is reacted with an anti-biotin labelled 10-methyl-N-tosyl-N-(2-carboxyethyl)-9-acridinium carboximide trifluoromethane sulfonate. Methods are also provided for using such a microparticle. Those methods of use can estimate transfer efficiency, calibrate optics, and measure membrane pore size of a chemiluminescence based instrument. Test elements for analytical instruments are also provided.