Comparison between pH 2·5 Alcian blue stain and Hale’s dialyzed iron technique for demonstrating acid mucin in colorectal carcinoma

Abstract

This study compared the value of pH 2·5 Alcian blue and Hale’s dialyzed iron methods for demonstrating acid mucin in colorectal carcinoma. A total of 40 colorectal biopsies from known positive cases were examined. Sections of the biopsies were stained using pH 2·5 Alcian blue method and Hale’s dialyzed iron technique, and classified as ‘good’ or ‘excellent’ according to staining intensity and efficiency, using a semi-quantitative scoring system. The pH 2·5 Alcian blue method was found to provide a higher frequency of ‘excellent’ scores compared to Hale’s dialyzed iron technique, 32 (80%) versus 21 (52.5%) respectively (P = 0·018). Both methods provide at least a minimal level of satisfactory staining results and seem to demonstrate the same amounts of acid mucins; however, if high quality Alcian blue dyes are available, pH 2·5 Alcian blue method is especially recommended to stain colorectal carcinoma acid mucins because it provides a stronger staining intensity and coloration compared to Hale’s dialyzed iron technique.