A simple method to determine the need for glacial acetic acid treatment of bloody ThinPrep Pap tests before slide processing

Navigating Practice Issues Related to the Unsatisfactory Cervicovaginal Papanicolaou Test: Survey Results of Laboratories Participating in the 2020 College of American Pathologists PAP Education Program

CONTEXT.—

Unsatisfactory Papanicolaou (Pap) tests pose a unique set of challenges to the laboratory with regard to their processing, review, reporting, and performance of human papillomavirus (HPV) testing. There are no standardized guidelines for the review process and handling of unsatisfactory Pap tests.

OBJECTIVE.—

To assess the current practice patterns regarding various aspects of the unsatisfactory Pap test, from processing to reporting, across laboratories worldwide.

DESIGN.—

A supplemental questionnaire was mailed to laboratories participating in the 2020 College of American Pathologists (CAP) Gynecologic Cytopathology (PAP Education) Program, requesting data regarding the unsatisfactory Pap test.

RESULTS.—

Of 1520 participating laboratories, 619 (40.7%) responded, and the responses of 577 laboratories were included for further analysis. Only 64.6% (373 of 577) laboratories used the unsatisfactory Pap test criteria as specified by the 2014 Bethesda System. About three-quarters of the respondents (433 of 576; 75.2%) routinely rescreened unsatisfactory Pap tests. Routine repreparation of such Pap tests was performed by 54.9% (316 of 576) of laboratories, and 52.0% (293 of 563) used glacial acetic acid for repreparing excessively bloody specimens. HPV test results were reported for unsatisfactory Pap tests, always or sometimes, by 62.4% (353 of 566) of respondents.

CONCLUSIONS.—

This CAP survey reveals important information regarding the practice patterns pertaining to several aspects of the unsatisfactory Pap test. It also provides valuable insight into the quality assurance measures that can be implemented for such tests. Future studies can further aid in the standardization of all components of the handling of unsatisfactory Pap tests for overall quality improvement.

Precancerous cervical lesions and HPV genotypes identified in previously unsatisfactory cervical smear tests after inexpensive glacial acetic acid processing

OBJECTIVE

To determine the effectiveness of using glacial acetic acid (GAA) to convert unsatisfactory bloody ThinPrep (TP) cervical smear test to satisfactory, and identify associated missed diagnoses and high-risk HPV (hrHPV) genotypes.

METHODS

In a retrospective descriptive cross-sectional analysis, all TP tests performed in Mississippi, USA, 2012-2016, were evaluated for unsatisfactory results owing to blood. Tests that were converted to satisfactory by GAA treatment, and corresponding anomalies and HPV genotypes were identified.

RESULTS

Among 106 384 TP tests, there were 1460 (1.37%) unsatisfactory results, of which 1442 (98.77%) were converted to satisfactory after GAA treatment. Laboratory preprocessing with GAA increased costs minimally. Precancerous lesions were detected in 166 (11.51%) of 1442 GAA-treated samples, of which 12 (7.2%) were high-grade lesions, 110 (66.3%) were atypical squamous cells of undetermined significance, and 63 (57.3%) tested positive for hrHPV. Of 60 genotyped samples, 39 (65%) had non-HPV16 and non-HPV18. Including mixed infections, 48 (80%) contained less-common hrHPV types, reflecting an unexpected distribution in bloody specimens.

CONCLUSIONS

GAA pretreatment of bloody TP tests would reduce the incidence of unsatisfactory results and missed high-grade lesions, and prevent the cost of repeat tests and delayed treatment. Clinicians without access to GAA should consider HPV testing.

Maximizing the adequacy of Hologic(®) Cervista(®) HPV HR results on ThinPrep(®) Pap samples treated with glacial acetic acid

BACKGROUND

Although glacial acetic acid (GAA) treatment of bloody cervical samples has reduced the rate of unsatisfactory Pap Tests, recent studies suggest that it may negatively impact high-risk (hr)-HPV test results. The objectives of this study were to compare the levels of genomic DNA between GAA treated and nontreated ThinPrep(®) samples using the Hologic(®) Cervista(®) HPV-HR assay and to compare the adequacy of the ThinPrep(®) Pap Test between aliquoted and nonaliquoted samples.

METHODS

Prior to GAA treatment, 2.5 ml of the cervical sample was prealiquoted from 102 bloody ThinPrep(®) vials. Both GAA treated and nontreated samples were analyzed for hr-HPV using the Cervista(®) HPV HR assay. The levels of genomic DNA were measured and compared between these samples. In addition, ThinPrep(®) Pap Test adequacy rates were calculated and compared on aliquoted and nonaliquoted cervical samples.

RESULTS

Of the 102 cervical samples, 95 (93%) nontreated aliquots contained satisfactory levels of genomic DNA as compared to 36 (35%) GAA-treated samples (p < 0.00001). Ninety-nine (97%) aliquoted cervical samples were satisfactory for cytologic evaluation as compared to 1,326 (96%) GAA treated samples from 2013 (nonaliquoted); not statistically significant (p = 0.7968).

CONCLUSION

The levels of genomic DNA were significantly decreased in GAA treated vs non-treated TP samples. Aliquoting from the TP sample prior to treatment with GAA enables accurate measurement of DNA without affecting the adequacy of the TP cytology slide.

The effectiveness of acetic acid wash protocol and the interpretation patterns of blood contaminated cervical cytology ThinPrep(®) specimens

BACKGROUND

ThinPrep(®) (TP) cervical cytology, as a liquid-based method, has many benefits but also a relatively high unsatisfactory rate due to debris/lubricant contamination and the presence of blood. These contaminants clog the TP filter and prevent the deposition of adequate diagnostic cells on the slide. An acetic acid wash (AAW) protocol is often used to lyse red blood cells, before preparing the TP slides.

DESIGN

From 23,291 TP cervical cytology specimens over a 4-month period, 2739 underwent AAW protocol due to initial unsatisfactory smear (UNS) with scant cellularity due to blood or being grossly bloody. Randomly selected 2739 cervical cytology specimens which did not undergo AAW from the same time period formed the control (non-AAW) group. Cytopathologic interpretations of AAW and non-AAW groups were compared using the Chi-square test.

RESULTS

About 94.2% of the 2739 cases which underwent AAW were subsequently satisfactory for evaluation with interpretations of atypical squamous cells of undetermined significance (ASCUS) 4.9% (135), low-grade squamous intraepithelial lesions (LSIL) 3.7% (102), and high-grade squamous intraepithelial lesions (HSIL) 1% (28). From the 2739 control cases, 96.3% were satisfactory with ASCUS 5.5% (151), LSIL 5.1% (139), and HSIL 0.7% (19). The prevalence of ASCUS interpretations was similar (P = 0.33). Although there were 32% more HSIL interpretations in the AAW group (28 in AAW vs. 19 in non-AAW), the difference was statistically insignificant (P = 0.18). AAW category; however, had significantly fewer LSIL interpretations (P = 0.02). The percentage of UNS cases remained higher in the AAW group with statistical significance (P < 0.01).

CONCLUSIONS

While AAW had a significantly higher percent of UNS interpretations, the protocol was effective in rescuing 94.2% of specimens which otherwise may have been reported unsatisfactory. This improved patient care by avoiding a repeat test. The prevalence of ASCUS and HSIL interpretations between AAW and non-AAW groups were comparable. Though not statistically significant, HSIL interpretations were relatively higher in the AAW group. LSIL interpretations showed lower prevalence in AAW group.

Effect of glacial acetic acid pre-treatment of cervical liquid-based cytology specimens on the molecular detection of human papillomavirus

OBJECTIVE

Cytology laboratories routinely treat cervical liquid-based cytology (LBC) specimens that are heavily contaminated with blood with glacial acetic acid (GAA) in order to lyse red blood cells and facilitate assessment. However, the impact on downstream human papillomavirus (HPV) detection is not well understood. This study examines the effect of GAA pre-treatment of ThinPrep(®) Preservcyt(®) specimens on the molecular detection of HPV.

METHODS

A panel of 150 routinely collected cervical LBC specimens was tested with two commercial HPV tests, the Abbott RealTime High Risk HPV test (rtHPV) and the Qiagen Hybrid Capture 2 High Risk HPV DNA test (HC2), as aliquots before and after GAA treatment. Statistical analysis was performed using McNemars test and Bland and Altman plots.

RESULTS

Agreement between the results of the rtHPV test on GAA-untreated and GAA-treated specimens was 95.7%, with no evidence of a significant difference in the distribution of the discrepant results (P = 0.414). HC2 test agreement on GAA-untreated and GAA-treated specimens was 91% at a cut-off of 1 relative light unit index (RLUI) and 92% at a cut-off of 2 RLUI. There was no evidence of a difference in the distribution of discordant results at a cut-off of 1 (P = 0.405) and 2 RLUI (P = 0.564).

CONCLUSIONS

GAA pre-treatment of cervical ThinPrep Preservcyt LBC specimens had little effect on the two commercial HPV tests used in this study. The impact of GAA treatment on HPV testing should, however, be validated for all HPV tests and all LBC collection media used in each particular diagnostic setting.

Gynecologic cytology on conventional and liquid-based preparations: a comprehensive review of similarities and differences

Liquid-based preparations (LBPs) have largely replaced conventional Papanicolaou smears (CPS) for cervical samples in the United States and in many other industrialized countries. The two FDA-approved LBP currently in use include ThinPrep (TP), (Hologic Inc., Bedford, MA) and SurePath (SP), (BD Diagnostic, Burlington, NC). Split-sample and direct-to-vial studies have shown that LBPs show an overall improvement in sample collection and processing, reduce artifacts that interfere in diagnosis, are more sensitive, can be utilized for ancillary tests and are a cost-effective replacement for CPS. Comparative analyses of diagnostic accuracy indicate that LBPs perform at least as well as CPS. However, the added advantages of standardized, automated preparations and screening, reduced unsatisfactory rate, improved specimen adequacy and ability to perform human papillomavirus (HPV) test, are enough to continue use of LBP. The cytologic features in LBP are similar to CPS with subtle differences, particularly in background information. There are also subtle differences between the two LBPs, SP and TP, which are reflective of different sampling devices, collection media, and processing techniques. Architecturally, LBP shows smaller cell clusters and sheets and more dyscohesion. Cytologically, enhanced nuclear features and smaller cell size are more prominent. Advances in liquid-based Papanicolaou's (Pap) test have lead to well-defined patient management guidelines by the American Society for Colposcopy and Cervical Pathology. Herein, we review these aspects of Pap test including, morphology, automation, ancillary tests (HPV and immunochemistry), pertinent QA/QC monitors, patient management guidelines, and review of pertinent literature.

Unsatisfactory rates vary between cervical cytology samples prepared using ThinPrep and SurePath platforms: a review and meta-analysis

OBJECTIVE

To compare unsatisfactory rates between the two major liquid-based cytology (LBC) platforms, namely ThinPrep (Hologic) and SurePath (Becton Dickinson).

DESIGN

The authors performed both a systematic review and a meta-analysis. Inclusion criteria were English language, data presented on unsatisfactory rates for either ThinPrep or SurePath, utilising actual patient samples (ie, not laboratory manipulated samples) and no manipulation using acetic acid to increase the satisfactory rate. The authors searched PubMed for articles using the keywords 'SurePath' or 'ThinPrep' and 'unsatisfactory'. References of retrieved studies were searched for additional articles. Key researchers in the field were also contacted.

PARTICIPANTS AND INTERVENTIONS

Eligible studies were reviewed for rates of unsatisfactory cervical cytology smears processed on either the ThinPrep or SurePath platforms (compared with a general linear model) or data on unsatisfactory rates for both platforms for the same laboratory and the same patient population (compared with a meta-analysis using a random effects model and pooled RR).

PRIMARY OUTCOME MEASURE

Unsatisfactory rate of cervical cytology smears.

RESULTS

A total of 1 120 418 cervical cytology smears were reported in 14 different studies using the SurePath platform for an overall unsatisfactory rate (weighted average) of 0.3%. 28 studies reported on 1 148 755 smears prepared using the ThinPrep platform for an overall unsatisfactory rate (weighted average) of 1.3%. The general linear model did not show a difference between LBC platforms when other variables were controlled for; however, the power to detect a difference (0.087) was very low. The meta-analysis performed on four studies where both ThinPrep and SurePath results were reported from the same laboratory showed fewer unsatisfactory tests from the SurePath platform (RR 0.44, 95% CI 0.25 to 0.77, p=0.004).

CONCLUSIONS

Multiple factors affect LBC unsatisfactory rates. In a meta-analysis, cervical cytology samples prepared on the SurePath platform show significantly fewer unsatisfactory smears than those prepared on the ThinPrep platform.

Improving cellularity and quality of liquid-based cytology slides processed from pancreatobiliary tract brushings

Cytology has been reported to have suboptimal sensitivity for detecting pancreatobiliary tract cancer in biliary tract specimens partly as a result of low specimen cellularity and obscuring noncellular components. The goal of this study was to determine if the use of a glacial acetic acid wash prior to processing would increase the cellularity and improve the quality of ThinPrep slides when compared to standard non-gyn ThinPrep processing. Fifty consecutive pancreatobiliary tract specimens containing 20 ml of sample/PreservCyt were divided equally for standard non-gyn ThinPrep (STP) and glacial acetic acid ThinPrep processing (GATP). A manual drop preparation was also performed on residual STP specimen to determine the number of cells left in the vial during STP processing. Twenty-six (52%) specimens had more epithelial cell groupings with the GATP methodology while 19 (38%) had equivalent cellularity with both methods. The STP method produced more epithelial cell groupings in 5 (10%) of the specimens. Of the 26 specimens that had less cells with the STP method, 14 (54%) had > or = 50 cell groupings on the manual drop slide processed from the residual STP specimen suggesting that many cells remain in the vial after STP processing. The GATP method was preferred in 25 (50%) of the specimens, the STP method in 5 (10%), while both methodologies provided similar findings in the remaining 20 (40%) of specimens. The data from this study suggests that the GATP method results in more cells being placed on the slide and was preferred over the STP method in a majority of specimens.

Repeating cytological preparations on liquid-based cytology samples: A methodological advantage?

This study investigates the rule that repeating cytological preparations on liquid-based cytology improves sample adequacy, diagnosis, microbiological, and hormonal evaluations. We reviewed 156 cases of pap-stained preparations of exfoliated cervical cells in two slides processed by DNA-Cytoliq System. After sample repeat/dilution, limiting factors affecting sample adequacy were removed in nine cases and three unsatisfactory cases were reclassified as satisfactory. Diagnosis was altered in 24 cases. Of these, the original diagnosis in 15 was atypical squamous cells of undetermined significance; after the second slide examination, diagnosis in 5 of the 15 cases changed to low-grade squamous intraepithelial lesion, 3 to high-grade squamous intraepithelial lesion, and 7 to absence of lesion. Microbiological evaluation was altered, with Candida sp. detected in two repeated slides. Repeat slide preparation or dilution of residual samples enhances cytological diagnosis and decreases effects of limiting factors in manually processed DIGENE DCS LBC.

"Sip volume" as a quality indicator in liquid-based cervical cytology

BACKGROUND

Introduction of nonmicroscopic cervical screening techniques creates the potential for liquid-based cytology specimens to be sent for human papillomavirus (HPV) testing, automated screening, or other assays prior to microscopic quality assessment. It was hypothesized that the volumes required to prepare ThinPreps ("sip volumes") represent indicators of specimen quality.

METHODS

A stratified random sample of 505 enrollment ThinPreps were assessed in the Atypical Squamous Cells of Undetermined Significance/Low-Grade Squamous Intraepithelial Lesion Triage Study (ALTS) to evaluate associations between sip volume and slide cellularity, cellular distribution, and clinical outcomes. Masked assessments included counting cells and qualitative evaluations.

RESULTS

Sip volumes were highest among women aged 18-19 or > or =35 years (P = .01), higher during the secretory menstrual phase (P < .0001), and lower among women with a history of Chlamydia infection (P = .04). Low cellularity was associated with Atypical squamous cells-cannot exclude high-grade squamous intra-epithelial lesion (ASC-H) interpretations at the clinical centers (P = .04). Sip volumes were related to cellularity (P < .0001) and cellular distribution (P < .0001). Sip volumes < or =2.0 mL were associated with lower cellularity and both low and high sip volumes yielded less homogeneous cell deposition. However, sip volume was unrelated to the overall performance of cytology and HPV testing.

CONCLUSIONS

Extremely low sip volumes are associated with hypocellular ThinPreps, and very low and high sip volumes more often show uneven cellular distribution. Although results of cytology and HPV testing in ALTS were generally unrelated to sip volume, results with other protocols or assays may vary, suggesting that microscopic assessment of specimens with extreme sip volumes prior to nonmicroscopic testing may be useful.

Protocol for the processing of bloody cervical specimens: Glacial acetic acid and the Thinprep® Pap test™

Since the utilization of the ThinPrep Pap Test in clinical practice, laboratories have strived to optimize cellular yields from cervicovaginal samples. Bloody specimens that often hamper cytologic interpretation and/or render a specimen unsatisfactory for diagnosis on conventional smears also affect ThinPrep preparations. Currently, there is no uniformly utilized method for the processing of bloody cervical specimens sent for analysis by the ThinPrep method. The purpose of this study is to present the protocol utilized by the University of Wisconsin Hospital and Clinics.

Reflex high-risk human papillomavirus DNA testing (Hybrid Capture 2) of bloody ThinPrep specimens with atypical squamous cells of undetermined significance interpretation

BACKGROUND

The current study was conducted to evaluate the efficacy of human papillomavirus (HPV) DNA testing of residual ThinPrep specimens, which were pretreated with acetic acid to optimize cellularity with a special focus on atypical squamous cells of undetermined significance (ASCUS) specimens.

METHODS

A total of 120 ThinPrep gynecologic samples were chosen for a pilot study including cases with a normal or abnormal interpretation and those with or without blood. Each residual specimen was divided into two portions. One portion was treated with glacial acetic acid (GAA) and the other half remained untreated. Both aliquots were tested for high-risk HPV DNA using the Hybrid Capture 2 test. After internal validation, reflex HPV DNA testing was performed on all consecutive 1776 ASCUS specimens including 98 acid-washed bloody specimens in routine practice.

RESULTS

Of the 120 specimens with paired aliquots, 117 specimens had concordant HPV DNA test results in the treated and untreated groups with a squared correlation coefficient value of 0.97 and a kappa value of 0.95. Subsequently, in the clinical setting, 43 of 98 (43.9%) acid-washed specimens and 845 of 1676 (50.4%) routine specimens with an ASCUS interpretation tested positive for high-risk HPV DNA. There was no statistically significant difference noted between these two groups with regard to age, percentage HPV DNA positivity, or viral load.

CONCLUSIONS

The pretreatment of bloody specimens with GAA did not appear to significantly affect high-risk HPV DNA testing in specimens with an ASCUS interpretation.