Which fixative is commonly recommended for lymph nodes?

• A. B-5
• B. Orth
• C. Zenker
• D. Zamboni

Answer: (A)

When fixing lymph nodes, the goal is to preserve delicate lymphoid architecture and nuclear detail quickly and convincingly so that routine stains and any ancillary tests come out reliable. An alcohol-based fixative that contains mercuric chloride with acetic acid achieves this well. It penetrates rapidly, preserves cellular and nuclear morphology effectively, and tends to produce clean, crisp histology for small, finely structured tissues like lymph nodes. This makes it a common recommendation for lymph node specimens, especially when quick, high-quality morphology is desired and the tissue benefits from strong nuclear detail.

Other fixatives can be more hazardous or create artifacts that are less ideal for lymph node morphology. For example, Zenker’s fixative uses mercuric chloride but also includes dichromate and is more hazardous and challenging to work with in routine processing. Orth’s fixative is less favored for routine lymph node work due to its composition and staining outcomes, and Zamboni’s fixative, while good for preserving antigenicity for some immunohistochemical stains, is not as universally preferred as a general fixative for lymph nodes.