The technique depicted is most likely which staining method?

• A. mucicarmine
• B. PAS
• C. Alcian blue pH 1.0
• D. colloidal iron

Answer: (A)

Mucin staining with mucicarmine highlights mucin-producing cells by coloring the mucin pink to red. The depicted image shows mucin-rich material within goblet cells or mucin-secreting tumor cells, which takes on a red/pink hue with this stain. This specificity helps distinguish mucin from other cellular components and confirms the presence of acidic mucins in the tissue.

In contrast, other stains would color mucin differently—for example, PAS turns mucin magenta, while Alcian blue (at its common pH) stains acidic mucins blue, and colloidal iron also yields blue staining for certain mucopolysaccharides. The red coloration of mucin with mucicarmine is the hallmark that makes this method the best fit for identifying mucin-containing cells in the image.