Method for determining antistreptolysin O antibody

A method for immunologically determining antistreptolysin O antibody, which comprises:

• (a) contacting a test sample solution containing antistreptolysin O antibody with a binding agent capable of specifically binding said antistreptolysin O antibody thereto, thereby selectively binding said antistreptolysin O antibody to said binding agent by antigen-antibody reaction, and
• (b) determining an amount of said antistreptolysin O antibody bound to said binding agent,
• said binding agent comprising a streptolysin O-immobilized carrier obtained by contacting a solution containing streptolysin O with a carrier having immobilized thereon at least one steroid represented by formula (1):
• ##STR7## wherein R.sup.1 is selected from the group consisting of a side chain moiety of cholesterol and a side chain moiety of cholic acid, wherein each of said side chain moieties is independently unsubstituted or substituted and independently saturated or unsaturated;
• R.sup.2 is hydrogen or hydroxyl;
• and each dashed line independently represents a single bond or no bond, such that each dashed line and a solid line adjacent thereto together independently form a double bond or a single bond.