When changing fixative from formalin to glyoxal, which assessment is likely necessary to ensure staining quality?

• A. Check for the correct staining of H pylori
• B. Reassess hematoxylin staining for color balance
• C. Verify DNA integrity after fixation
• D. Update embedding resin compatibility

Answer: (A)

Switching fixatives can change how tissues react to stains, so you need to validate the staining performance on the most diagnostically relevant targets. Glyoxal can alter tissue preservation and stain uptake differently from formalin, and small organisms like H. pylori are particularly sensitive to these changes. If H. pylori staining remains reliable after the fixative change, it’s a strong indicator that the overall staining quality is preserved for key diagnostic targets. While other checks (like hematoxylin color balance, DNA integrity, or resin compatibility) are useful in their own right, they don’t test the staining performance for a critical diagnostic visualization as directly as confirming H. pylori staining.