Comparison of cell block preparation methods for nongynecologic ThinPrep specimens.

The purpose of this study was to compare four cell block (CB) methods in the setting of nongynecologic ThinPrep (TP) specimens. 48 CBs were prepared from 12 nongynecologic TP specimens using the following CB methods: (1) Inverted filter sedimentation (IFS); (2) Thrombin method; (3) Albumin method; (4) Simple sedimentation. Each CB was assigned a cellularity score: 0 no cells, 1+ hypocellular, 2+ hypocellular with tissue fragments, 3+ cellular. A score of 2+ or 3+ was given for 11/12 of thrombin, 7/12 IFS, 5/12 albumin, and 2/12 simple sedimentation CBs. Thrombin CBs demonstrated a pale background clot with evenly distributed cells. Albumin CBs had a cracked uneven background. IFS CBs had a clear background, but were technically difficult and cells appeared artifactually crowded. In the setting of nongynecologic TP specimens, the thrombin CB was easily prepared and produced the best CB in regards to cellularity, cell distribution, and background quality.