Resolving ASCUS without recourse to HPV testing: Manual reprocessing of residual automated liquid-based cytology (ALBC) material using manual liquid-based cytology (MLBC)

Abstract

We show that residual cell material from ThinPrep PapTest (Cytyc Corporation, Boxborough, MA) atypical squamous-cells of undetermined significance (ASCUS) cases may be manually reprocessed to triage women into actionable diagnostic categories (HSIL, LSIL, and Negative). Material remaining from each of 358 ThinPrep ASCUS cases was manually reprocessed as two slides, labeled "A" and "B." Interobserver agreement between case contributors (CCs) and three sequential reviewers (SRs) was analyzed with 186 cases (Study 1), and diagnostic reproducibility between SRs was examined with an additional 172 cases (Study 2). In Study 1, CCs classified 33% of cases as LSIL or greater, SRs classified 60% as LSIL or greater, and there was 58% diagnostic agreement between CCs and SRs. No "Negative" case assignment by one group afforded an "HSIL" assignment by the complementary group. In Study 2, there was 95% agreement between SRs A slide and B slide diagnoses with 54% of A slides and 55% of B slides classified as LISL or greater. Again, no "Negative" case assignment to one slide afforded an "HSIL" assignment to the complementary slide. Overall, 12.6% of the 358 cases showed HSIL, and all HSILs by one observer group were ASCUS or greater by the complementary observer group. Using manual reprocessing beyond the 21-day specimen outdate for HPV testing by the Hybrid Capture II High Risk HPV test (HR-HCII; Digene Corporation, Beltsville, MD), many ThinPrep ASCUS cases were reclassified as LSIL or HSIL. The 12.6% HSIL proportion of this study approximated the 11.5% CIN 2 or greater proportion of the ALTS ASCUS arm. Similar to ALTS, manual liquid-based cytology (MLBC) would have referred nearly 60% of women to colposcopy for a definitive diagnosis of HSIL or LSIL without resorting to HPV testing. These data demonstrate that many cases of automated liquid-based cytology (ALBC)-diagnosed ASCUS represent unrecognized SIL, which is present in the ALBC specimen vial at the time the ASCUS diagnosis is rendered.

Testing automated liquid-based cytology samples with a manual liquid-based cytology method using residual cell suspensions from 500 ThinPrep cases

“…In a recent study, we reprocessed 358 ThinPrep ASCUS cases using an earlier embodiment of present MLBC method and, similar to Guo et al, found 12.6% HSILs and 46.1% LSILs-only here, in material that was present within residual sample suspensions originally diagnosed as ASCUS on ThinPrep slides. 13 These data suggest that some portion of ''sampling error'' occurs, not at the level of the patient, but at the level of the specimen vial, probably when vials contain only rare dysplastic cells.…”

Determination of HPV DNA viral load by hybrid capture assay and its association with cytological findings

“…Although new alternatives have been proposed, there is a consensus on the HC indication for cases diagnosed as ASCUS (15,16) . The use of the diagnostic tests for HPV DNA in combination with cytology has been recommended by some authors because it enhances the performance of both tests (6,7) .…”

Morphologic, Patient and Interpreter Profiles of High-Risk Human Papillomavirus–Positive vs. –Negative Cases of Atypical Squamous Cells of Undetermined Significance

“…One technique, described by Maksem et al, 15 suggests manually reprocessing residual automated liquid-based cytology material using a modified version of Saccamono's technique. 15,16 This process is described as being simple and rapid, and requires only a conventional centrifuge, a vortex mixer and a pipettor. Additional disposable items would be required such as glass slides, test tubes, disposable pipettes, fixative vials and necessary reagents.…”