After completion of a Gordon and Sweet's technique, the reticulum is demonstrated as pale grey fibers. Which of the following would be the possible cause?

• A. The time in the Ferric Ammonium Sulphate was too short
• B. The mordant was too strong
• C. The slide was not deparaffinized
• D. The stain was too concentrated

Answer: (A)

During Gordon and Sweet's reticulin stain, reticular fibers should appear dark against a pale background. The ferric ammonium sulfate acts as the mordant that sensitizes and anchors silver to the reticular fibers. If the tissue is left too briefly in the ferric ammonium sulfate solution, the fibers become inadequately mordanted, so less silver is deposited and reduced during development. The result is pale grey fibers instead of the expected dark reticulum. If the mordant were too strong, the fibers would usually darken more, not remain pale; not deparaffinizing or using an overly concentrated stain would cause other staining problems or background issues rather than selectively pale fibers.