Frozen sections can be stained with toluidine blue O.

• A. Yes
• B. No
• C. Only after fixation
• D. Only on paraffin sections

Answer: (A)

Staining frozen sections with toluidine blue O is feasible because this dye is a quick, water-soluble basic stain that works well on unfixed cryostat sections. It provides rapid nuclear detail and overall tissue contrast, which is ideal for intraoperative or rapid diagnostic assessment without the need for fixation. Since the tissue in frozen sections is not fixed, using an aqueous stain like toluidine blue O fits the workflow and allows immediate evaluation. Therefore, frozen sections can indeed be stained with toluidine blue O.