Modified Plasma-Thrombin Method of Cell Block Preparation for Fine-Needle Aspiration Biopsies in Resource-Limited Settings

Abstract

Objectives: The plasma-thrombin method is commonly used to make cell blocks from fine-needle aspiration (FNA) samples but requires centrifugation. We describe a modification to this method that does not require centrifugation for use in resource-limited settings. Methods: Pooled fresh plasma is aliquoted into 2-mL Eppendorf tubes and the FNA sample directly rinsed into the plasma. Two drops of reconstituted thrombin are added and gently mixed. A cell clot is transferred to a tissue bag, fixed in formalin, and processed. This method was applied to FNA samples from 44 patients presenting to the Mbarara University of Science and Technology FNA clinic. Results: The cell blocks were less cellular than the smears but contained adequate material to confirm morphologic impression or perform immunocytochemistry in 36 of 44 cases (82% adequacy rate). Conclusions: The modified plasma-thrombin method is a reliable cell block preparation method that can be easily applied in resource-limited settings.