Which artifact in Oil Red O staining is linked to errors during coverslip application?

• A. Fat droplets in tissue spaces
• B. Nuclear clumping
• C. Excess nuclear staining
• D. No color change

Answer: (A)

Oil Red O detects neutral lipids in frozen sections, so preserving lipids and using an aqueous mountant is essential. When the coverslip is applied, excessive pressure or incompatible mounting medium can push or release lipids from the tissue, causing them to collect as red droplets in the extracellular spaces. This creates fat droplets in tissue spaces as an artifact rather than true lipid localization. To prevent it, mount with an appropriate aqueous medium and apply the coverslip gently to avoid squeezing lipids out of the tissue.