Best routing clearing agent for urgent biopsies?

• A. Benzene
• B. Chloroform
• C. Xylene
• D. Toluene

Answer: (A)

Clearing agents are used after dehydration to remove alcohol and render the tissue amenable to paraffin infiltration by making it miscible with wax. When a biopsy is urgent, speeding this step can shave precious time off the overall processing. Benzene, as a very effective solvent with rapid penetrating power and strong ability to displace alcohol, clears tissue quickly and thus minimizes delay before embedding. That speed is why it has historically been favored for urgent specimens.

However, benzene is highly toxic and carcinogenic, so modern practice avoids it in favor of safer clearing agents such as xylene or other less hazardous substitutes, even though they may not clear as rapidly.