It is all in the bag: collodion bag versus HistoGel cell block method.

INTRODUCTION: We performed a comparison of cell blocks prepared with the collodion bag and HistoGel to evaluate the ease of embedding and cutting, performance with low cellularity specimens, time and cost per specimen, and value to support immunohistochemistry and molecular diagnostics. MATERIALS AND METHODS: We processed 11 fresh, unfixed effusions using both the collodion bag and the HistoGel cell block preparation methods. Six immunohistochemistry stains were tested on 2 of the body fluids. DNA was extracted and quantified, and polymerase chain reaction cycle thresholds were evaluated from cell blocks prepared from 5 of the body fluids. The comparison parameters included embedding difficulty, cutting resistance, adequacy, cell yield, cell preservation, immunohistochemistry stain quality, DNA quantity, integrity, and purity. The time and cost to prepare each specimen was compared using normalized values for preparation of specimen, cost per year, and cost per specimen. RESULTS: Each parameter was assessed for both cell block preparation methods. All 3 of the samples with moderate or poor cell yield were low-volume (5-mL) samples prepared with the HistoGel method. In contrast, the collodion bag method produced a good yield with all three 5-mL samples. DNA recovery was greater in the collodion bag method. Similar crossing threshold values in purity reactions indicated equally high-quality matrix properties for the collodion bag and HistoGel preparations. Preparation of the specimen was 10 minutes faster with the collodion bag method, and the cost for the collodion bag method was $0.24 more expensive per cell block than using the HistoGel. CONCLUSIONS: The collodion bag method produced superior cell blocks for both morphologic and molecular studies more consistently, with lower volume specimens and with less time per specimen.

Rapid prescreening is as effective at reducing screening error as postscreening with the FocalPoint automated screening device.

Both manual (rapid prescreening) and automated methods have been devised to reduce screening error compared with routine review of 10% of negative gynecologic cases. To date these two methods have not been compared. A total of 5,139 liquid-based (SurePath Pap Test, BD Diagnostics) cases were subjected to 100% rapid prescreening and routine manual screening. All cases diagnosed as negative on routine screening were placed on the FocalPoint (BD Diagnostics, Franklin Lakes, NJ) automated screening device. All cases that were negative on routine screening and abnormal on rapid prescreening or in the top 15% of cases by FocalPoint were rescreened and a final diagnosis obtained. Cases were blinded during rapid prescreening and routine manual screening. Abnormal was defined as any diagnosis of atypical squamous cells (ASC) or worse. A total of 427 (8%) of cases were abnormal on routine screening. The sensitivity of rapid prescreening was 44.6%. Rapid prescreening identified an additional 14 abnormal cases (13 ASC and 1 LSIL) and FocalPoint identified nine cases (eight ASC, one LSIL) that were not detected by routine screening. Three of these cases were detected by both methods. The sensitivity of routine screening was 93.1%. Rapid prescreening increased the overall sensitivity significantly (96.0%, P = 0.04); FocalPoint increased the sensitivity but this change was not significant (95.0%, P = 0.21). Estimated screening time was 30 seconds for rapid prescreening and 6 minutes for routine screening with the result that rapid prescreening required 2,570 minutes while review of the FocalPoint Slides required 2,694 minutes. The sensitivity of routine screening in the second half of the study (95.3%) was higher than that in the first half of the study (91.6%) but the difference was not significant (P = 0.11). Rapid prescreening is as effective as directed review using FocalPoint at reducing screening errors and requires no additional screening time. Continued use of these methods may improve the sensitivity of routine screening