contacting a serum sample with an antibody which binds to wherein k u2014 k u2014 k is hydroxylysyl pyridinoline or lysyl pyridinoline and correlating any detected binding to resorption of non mineralized type ii collagen in vivo in a second embodiment the invention provides an improved method of analyzing a body fluid sample for the presence of an analyte indicative of a physiological condition including the steps of contacting the body fluid sample with an antibody which binds to the analyte detecting binding of the antibody in the body fluid sample and correlating any detected binding to the physiological condition the improvement comprising contacting a serum sample with an antibody which binds to wherein k u2014 k u2014 k is hydroxylysyl pyridinoline or lysyl pyridinoline and correlating any detected binding to resorption of mineralized type ii collagen in vivo in a third embodiment the invention provides an improved method of analyzing a body fluid sample for the presence of an analyte indicative of a physiological condition including the steps of contacting the body fluid sample with an antibody which binds to the analyte detecting binding of the antibody in the body fluid sample and correlating any detected binding to the physiological condition the improvement comprising contacting a urine sample with an antibody which binds to wherein k u2014 k u2014 k is hydroxylysyl pyridinoline or lysyl pyridinoline and correlating any detected binding to resorption of both non mineralized and mineralized type ii collagen in vivo in a fourth embodiment the invention provides an improved method of analyzing a body fluid sample for the presence of an analyte indicative of a physiological condition including the steps of contacting the body fluid sample with an antibody.