Assuring the quality of quality assurance: seeding abnormal slides into the negative Papanicolaou smears that will be rapid rescreened

Performance of rapid prescreening and 100% rapid review as internal quality control methods for cervical cytopathology

BACKGROUND

An objective of quality control for cervical cytopathology is reducing high rates of false-negative results of laboratory tests. Therefore, methods to review smears such as rapid prescreening and 100% rapid review, which have shown better performance detecting false-negative results, have been widely used. The performance of rapid prescreening and the performance of 100% rapid review as internal quality control methods for cervical cytology examinations were evaluated.

METHODS

For 24 months, 9318 conventional cervical cytology smears underwent rapid prescreening and routine screening. The 100% rapid review method was performed for 8244 smears classified as negative during routine screening. Any discordant results underwent detailed review to define the final diagnosis. This was considered the gold standard for evaluating the performance of rapid prescreening and 100% rapid review.

RESULTS

Routine screening showed increases of 13.3% and 11.5% in the detection of abnormal smears with rapid prescreening and 100% rapid review, respectively. The relative percentage variation showed a 38.1% increase in the diagnosis of atypical squamous cells of undetermined significance with routine screening and rapid prescreening and a 12.5% increase in the diagnosis of atypical squamous cells, cannot exclude high-grade squamous intraepithelial lesion with both rapid prescreening and 100% rapid review. Sensitivity rates of rapid prescreening and routine screening were 48.2% and 83.2%, respectively. Sensitivity rates of rapid prescreening and 100% rapid review were 65.7% and 57.8%, respectively, for detecting false-negative results.

CONCLUSIONS

Inclusion of rapid prescreening and/or 100% rapid review improved the diagnostic sensitivity of the cervical cytology examination and reduced false-negative results of routine screening and can provide good quality control.

Pap smears with glandular cell abnormalities: Are they detected by rapid prescreening?

BACKGROUND

Rapid prescreening (RPS) is one of the quality assurance (QA) methods used in gynecologic cytology. The efficacy of RPS has been previously studied but mostly with respect to squamous lesions; in fact, there has been no study so far specifically looking at the sensitivity of RPS for detecting glandular cell abnormalities.

METHODS

A total of 80,565 Papanicolaou (Pap) smears underwent RPS during a 25-month period. A sample was designated as "review for abnormality" (R) if any abnormal cells (at the threshold of atypical squamous cells of undetermined significance/atypical glandular cells [AGC]) were thought to be present or was designated as negative (N) if none were detected. Each sample then underwent full screening (FS) and was designated as either R or N and also given a cytologic interpretation.

RESULTS

The final cytologic interpretation was a glandular cell abnormality (≥AGC) in 107 samples (0.13%); 39 of these (36.4%) were flagged as R on RPS. Twenty-four patients (33.8%) out of 71 who had histologic follow-up were found to harbor a high-grade squamous intraepithelial lesion or carcinoma; 13 of those 24 Pap smears (54.2%) had been flagged as R on RPS. Notably, 11 AGC cases were picked up by RPS only and not by FS and represented false-negative cases; 2 of these showed endometrial adenocarcinoma on histologic follow-up.

CONCLUSIONS

Pap smears with glandular cell abnormalities are often flagged as abnormal by RPS, and this results in a sensitivity of 36.4% (at the AGC threshold). Most importantly, some cases of AGC are detected on Pap smears by RPS only, and this demonstrates that RPS is a valuable QA method.

Internal quality control for cervical cytopathology: comparison of potential false-negatives detected at rapid prescreening and at 100% rapid review

OBJECTIVE

To evaluate the performance of rapid prescreening (RPS) and 100% rapid review (RR-100%) as internal quality control (IQC) methods assessed by outcome at colposcopy, histopathology and repeat cytopathology for cases with false-negative results on cervical cytopathology at routine screening (RS).

STUDY DESIGN

Out of 12,208 cytology smears analyzed, 900 were abnormal. Of these, 656 were identified at RS, and 244 were false-negative, with 90.2% identified at RPS and 57.4% at RR-100%. Of the 900 abnormal cases, 436 were submitted for additional testing.

RESULTS

Of the 244 women with cytopathological abnormalities identified only by the IQC methods, 114 had supplementary examinations: 35 were submitted for colposcopy, 22 for biopsy and 99 for repeat cytopathology. The sensitivity of RPS for the detection of abnormalities identified on colposcopy, histopathology and repeat cytopathology was 87.5% (95% CI 67.6-97.3), 82.4% (95% CI 56.6-96.2) and 95.7% (95% CI 85.2-99.5), respectively. The sensitivity of RR-100% was 54.2% (95% CI 32.8-74.4), 52.9% (95% CI 27.8-77.0) and 47.8% (95% CI 32.9-63.1), respectively. RPS was more sensitive than RR-100% when compared to the findings on colposcopy (p = 0.011) and repeat cytopathology (p = 0.000). When compared to colposcopy, histopathology and repeat cytopathology, the sensitivity of RS was 83.2% (95% CI 76.1-88.9), 85.7% (95% CI 78.1-91.5) and 73.3% (95% CI 66.0-79.7), respectively.

CONCLUSION

RPS performed better than RR-100% when compared to the results of colposcopy and repeat cytopathology.

The value of expert review in prospective trials of automated assisted screening devices

Previous prospective studies of automated assisted gynecologic screening devices have used a panel of experts for truth determination. We sought to determine the value of this practice. The relative sensitivity of the devices compared with manual screening was calculated using an expert panel for truth determination and compared using likelihood ratios to the relative sensitivity assuming all abnormal cases were truly abnormal. These results show that expert panel review has no significant effect on relative sensitivity at the threshold of ASCUS+ but may have an effect at HSIL+. Trials without expert consensus review may be compared to those with expert consensus review at the threshold of ASCUS+ but may not be reliable at the threshold of HSIL+ without additional confirmatory data.

Prospective and retrospective review of gynecologic cytopathology: findings from the College of American Pathologists Gynecologic Cytopathology Quality Consensus Conference working group 2

CONTEXT

Two quality metrics for gynecologic cytology are the subject of this review: "prospective rescreening" and "retrospective rescreening."

OBJECTIVE

To offer consensus best practice approaches based on the College of American Pathologists' laboratory-based survey funded by the Centers for Disease Control and Prevention.

DESIGN

The College of American Pathologists submitted a paper-based survey to 1245 laboratories. After review of initial results, follow-up Web-based survey results, and a literature review, consensus best practice statements were presented at a national consensus conference. These statements were discussed and voted upon by conference participants. Results.-A total of 541 laboratories responded to survey questions about prospective and retrospective rescreening. Most laboratories (>85%) prospectively rescreen more than 10% of Pap tests interpreted as negative for intraepithelial lesion or malignancy. Most (72%) report inclusion of less than 20% high-risk cases. Most laboratories use multiple measures to define "high risk." Most laboratories (96.2%) retrospectively rescreen Pap tests from the preceding 5 years only. In most laboratories (71.4%) only Pap test results with high-grade squamous intraepithelial lesion or worse prompt retrospective review.

CONCLUSIONS

The number of Pap tests from high-risk patients should be maximized in prospective and retrospective rescreening. Unsatisfactory Pap tests should also be included. All readily identifiable high-risk human papillomavirus-positive cases with an interpretation of negative for intraepithelial lesion or malignancy should be prospectively rescreened. Cervical biopsy results with high-grade cervical intraepithelial neoplasia or worse (CIN 2+) should trigger retrospective rescreening. Regular feedback should be provided to cytotechnologists and cytopathologists. Upgraded diagnoses from negative for intraepithelial lesion or malignancy to atypical squamous cells, cannot exclude high-grade squamous intraepithelial lesion, should be monitored.

Controls in quality assessment in gynecologic cytology: A rational approach to workload limits for the ThinPrep imaging system

Major components of good quality assurance (QA) in cytology laboratories are measuring the screening accuracy of cytotechnologists (CTs) and determining appropriate workload limits for them. Currently, the FDA approved workload limits for image assisted Paps, however, are too high. In addition, the CLIA 88 mandated QA measures, by themselves, are insufficient to accurately measure the screening performance of CTs. Although the use of "controls" is fundamental to good practice in the clinical laboratory; this has not been emphasized in gynecologic cytology. In this review, we underscore the importance of using controls, such as monitoring morning and afternoon abnormal rates, in assessing CT performance and assigning reasonable workload limits. Using controls, however, requires significant alteration in the laboratory workflow, and much lower and variable workload limits for CTs, compared to those approved by FDA.