To correct incomplete infiltration, how many changes of paraffin wax are recommended?

• A. 1-2
• B. 2-3
• C. 3-4
• D. 4-5

Answer: (B)

Incomplete infiltration happens when the clearing agent isn’t fully replaced by paraffin, so the tissue doesn’t become fully penetrated and embedded. Repeated exchanges with fresh molten paraffin ensure the clearing agent is gradually driven out and replaced, giving a uniform, solid block that sections cleanly. In practice, two to three changes of fresh paraffin are typically used to achieve thorough infiltration. One change usually isn’t enough, while four or five is more than necessary for most specimens, unless the tissue is unusually large or dense.