The present invention provides a method for detecting modified LDL, abnormal cells or bacteria using an intermolecular interaction analysis method, in which a region involved in ligand recognition by a receptor is expressed, without modification or as a biotinylated protein, in cells or in a test tube, and thereafter, the expressed region or the expressed biotinylated protein is immobilized via avidin or streptavidin to a solid phase while the orientation thereof is maintained, and the immobilized protein is utilized; and a kit for detecting the modified LDL or the like.