Naphthol AS-D chloroacetate esterase reaction. Systematic modifications for optimization to smears and sections.

Currently used methods for naphthol AS-D chloroacetate (NASDCA) esterase reactions can be divided into 3 groups according to the coupler used, i.e., fast garnet GBC, pararosanilin, and new fuchsin. These 3 groups were systematically modified with regard to modes of fixation and incubation in order to develop optimal methods for their application on sections of formalin-fixed and paraffin-embedded tissue as well as blood smears. After obtaining the optimal modifications for each of the 3 coupler methods, comparison was made between the 3 optimal methods for blood smears and the 3 for tissue sections. For blood smears, the methods using either fast garnet GBC or new fuchsin as coupler were found to be equally excellent, while the method using pararosanilin as coupler was not as superior. For tissue sections, the methods using either fast garnet GBC or pararosanilin were found to be equally excellent, while the method using new fuchsin was not as superior. Thus, only the method using fast garnet GBC as coupler was found excellent for both purposes. It was also found that bone marrow biopsies routinely processed through formalin-fixation would yield excellent NASDCA esterase reaction provided Plank and Rychlo's method instead of EDTA was employed for decalcification.