B-5 fixative is recommended for which tissue type?

• A. Lymph nodes
• B. Liver
• C. Skin
• D. Muscle

Answer: (A)

B-5 fixative is especially good for lymphoid tissue because its chemical mix is tailored to preserve delicate cellular detail and architecture found in lymph nodes. The combination of alcohol, formalin, and acetic acid fixes quickly and penetrates well, while the acetic acid component helps preserve nuclear detail and chromatin as well as the fine cytoplasmic features of lymphocytes. This results in clear demonstration of germinal centers, sinuses, and the overall lymph node architecture, which is crucial for accurate evaluation.

Other tissues like liver, skin, or muscle are generally adequately fixed with standard fixatives (often formalin alone), and the use of B-5 can introduce artifacts or less optimal staining for those tissues.