Cedarwood oil is listed as which type of agent in tissue processing?

• A. Clearing
• B. Dehydrant
• C. Infiltration/Embedding
• D. Fixative

Answer: (A)

Cedarwood oil is used during the clearing step of tissue processing. Clearing agents replace the dehydrating solvent (the alcohol used after dehydration) and render the tissue transparent while making it miscible with paraffin. Cedarwood oil serves this role because it dissolves in paraffin and prepares the tissue for infiltration with molten paraffin wax. It is not a dehydrant, nor an infiltration medium, nor a fixative. Dehydrants remove water, infiltration/embedding involves introducing paraffin, and fixatives preserve tissue structure by cross-linking proteins.