The present invention lies in the field of visualization and quantification of immobilized targets in samples using immunochemical means. In particular, the invention relates to a method and reagents for detection, visualization and quantification of a molecular target in immunostained histological samples using particular compositions of the target specific binding agent. Methods and compositions of the invention are suitable for any assay that uses a target visualization system in histological samples based on detection of the target by the target specific binding agent. The methods and compositions are useful for evaluation of targets that are biomarkers of diseases in medical diagnostic.