To treat a physiologically active substance useful for clinical tests, etc., by bonding the physiologically active substance in a sample to a granular solid-phase support treated with a protein (conjugate), directly using the resultant physiologically active substance for an enzymic reaction and realizing a high detecting ability in a short time.

When a physiologically active substance in a sample is bonded to a granular solid-phase support comprising an organic polymeric material or an inorganic material such as a metal, a metallic oxide, a silica or a glass and the physiologically active substance in a state thereof bonded to the solid-phase support is used for an enzymic reaction and thereby is treated, the solid-phase support is treated with a protein such as an albumin, a globulin, various antibodies, casein or a blood serum protein or a protein conjugate comprising the protein, a saccharide, a lipid, a nucleic acid, a membrane, etc. Thereby, the physiologically active substance in a state thereof retaining high activities can be used for the enzymic reaction to realize a high detection ability in the field of clinical tests, etc., and the time can remarkably be shortened to treat the physiologically active substance before or after bonding the physiologically active substance to the solid-phase support.