What is the preferred fixative for the technique shown in the image?

• A. Formalin
• B. Bouin's solution
• C. Ethanol
• D. Glutaraldehyde

Answer: (A)

For routine histology where tissue is fixed, embedded in paraffin, and stained with standard stains like hematoxylin and eosin, neutral buffered formalin is used because it preserves overall tissue architecture well and is compatible with the paraffin process and common staining. It crosslinks proteins just enough to maintain morphological details without overly distorting structures, and it’s a reliable, widely supported fixative for many tissue types. Other fixatives have specialized uses: Bouin’s solution can give excellent nuclear detail but contains picric acid and can color tissues and interfere with some stains, making it less ideal for routine paraffin sections; ethanol fixes by dehydration and is typically used for cytology or specific downstream applications, not for preserving architecture for paraffin embedding; glutaraldehyde provides superb preservation for electron microscopy but causes rigid, heavily crosslinked tissue that isn’t suitable for routine light microscopy. So the image’s technique is best served by neutral buffered formalin.