Cell block cytology

Cell block cytology is a technique used in cytopathology (in addition to smears) for evaluation of tissue from fine needle aspirations (FNA) or fluid aspirations.

Multiple different protocols exist for processing a cell block, but the fundamental principles are the same:

• fragmentary bits of tissue (e.g. remnant tissue in a thyroid biopsy needle) are collected into a 40-50 mL container filled with a preservative solution
• plasma and thrombin may be added to the solution to coagulate the red blood cells in the solution
• the cells in solution are then concentrated via centrifuge
• the remaining cell "pellet" is processed and reviewed

Cell block techniques can be used in any situation, but are particularly useful in percutaneous needle biopsies that may yield only scant tissue, such as in thyroid or lung biopsies.