This invention relates to methods for detecting, identifying and quantifying enzymes, for example, human proteolytic enzymes. The method broadly comprises forming an immobilized or insoluble complex comprising enzyme, enzyme inhibitor and enzyme inhibitor-antibody reactive site and then detecting and identifying, preferably quantitatively, one or more enzymes bound to the complex. In a preferrend embodiment, a matrix, e.g. solid or semisolid surface or permeable matrix, has affixed thereto enzyme inhibitor-antibody or an immunologically active (inhibitor binding) fragment of such an antibody. This insoluble enzyme inhibitor interacting matrix is then contacted with biological fluid, e.g. body fluid, to bind one or more predetermined enzyme inhibitor-enzyme complexes, if present in the biological fluid. The bound enzyme is then detected, identified and preferably quantified.