The cell block is an ancillary technique used in cytology to increase the diagnostic accuracy in the analysis of effusions and aspirations. In our laboratory, we implemented the routine use of the Thromboplastin-Plasma Cell-Block (TP-CB) technique because it is simple, reproducible and has low cost. The aim of this prospective study was to proof the utility of performing routine cell blocks in non-gynecologic cytology by comparing the diagnostic concordance, cellularity, and contribution to diagnosis from paired TP-CB and Conventional Cytological (CC) preparations. For this, all non-gynecologic specimens including effusions, body fluids and aspirations, were collected for an 8-month period. A total of 179 TP-CBs were prepared from the remaining fluid following CC preparations. Absolute concordance was found in 81.6% cases between both techniques (κ = 0.56). The cell block aided the diagnosis in 28% of cases and ICC studies were done in 12%. The use of routine TP-CB complements and enhances the diagnostic accuracy of CC, allows the performance of ancillary studies and improves the diagnostic approach and treatment.