American Society for Clinical Pathology (ASCP) Histotechnologist Practice Test

What does tissue processing primarily include?

1. Embedding and staining only

2. Dehydration, clearing, infiltration

3. Microscopy procedures alone

4. None of the above

The correct answer is: Dehydration, clearing, infiltration

Tissue processing is a critical step in histotechnology that prepares tissue samples for microscopic examination. It generally involves several key stages, primarily including dehydration, clearing, and infiltration. Dehydration removes water from the tissue, typically through a series of alcohol solutions of increasing concentrations. This step is essential because most embedding media are not water-soluble. Following dehydration, the clearing process is performed, which replaces the alcohol with a substance that is miscible with the infiltration medium, often using xylene or toluene. Finally, infiltration involves embedding the tissue in a support medium, like paraffin, which solidifies and helps maintain the tissue structure for sectioning. The other options do not fully encompass the tissue processing stages. While embedding and staining are important in the overall workflow, they do not represent the primary processes involved in tissue processing itself. Microscopy procedures, while critical in analyzing processed tissues, occur after processing and are not part of the processing stages. Therefore, the correct answer highlights the essential steps of dehydration, clearing, and infiltration, which are crucial for preparing tissues adequately for further analysis.