100% rapid (partial) rescreening for quality assurance

Quality assurance of anatomic pathology diagnoses: Comparison of alternate approaches

OBJECTIVES

Traditionally, a 10% review has been the basis for quality assurance programs in anatomic pathology. The effectiveness of such reviews has been questioned and alternative methodologies suggested. The study investigates the error detection rates for four quality assurance protocols.

METHODS

The detection rate for diagnostic errors in surgical pathology was calculated over a one year period using four different review procedures comprising: random 10% review, correlation of internal and external diagnoses following solicited external expert opinion, correlation of internal diagnoses with outside diagnoses in cases sent for review at a second institution treating the patient along with a focused review of dermatopathology cases over a 3 month period. Error rate was expressed as percentage of reviewed cases where the initial diagnosis differed from the review diagnosis. Error rates detected by each method were compared among the methods RESULTS: The 10% random review detected seventeen errors in 2147 cases (0.8%). Solicited case consultations requested by clinicians or internal pathologists detected five diagnostic errors in seventy cases (7.1%). Unsolicited reviews by outside institutions in the course of patient care detected three diagnostic errors in 190 cases (1.6%). Review of the dermatopathology material disclosed 5 diagnostic errors in 59 cases (8.5%).

CONCLUSIONS

Focused reviews initiated by diagnostic concerns of a clinician or pathologist, unsolicited reviews because of treatment at another institution and sub-specialty based reviews appear to be more effective in detecting diagnostic errors than the 10% random review. Quality assurance programs should include focused reviews in addition to 10% random review to maximize error detection.

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.

Rapid prescreen of cervical liquid-based cytology preparations: results of a study in an academic medical center

A rapid prescreening or rapid rescreening method for quality assurance in cervical cytology has been used in Europe and in Canada but has not been accepted in the United States. The rapid prescreen method was tested in a cytology laboratory that serves an academic medical center with a high-risk population for cervical cancer. For a period of 3 months, a tray of 20 sequentially numbered Surepath™ liquid-based preparations, randomly selected from the cervical cytology daily workload, were each prescreened in a random fashion for 1 minute. Experienced cytotechnologists performed the rapid prescreen. Results were recorded as negative, further review needed, or epithelial cell abnormality, category specified. The 20 cervical cytology preparations were then replaced in their same position in the daily workload for routine screening performed by another cytotechnologist. Final interpretation was by a cytopathologist as requested or required by Clinical Laboratory Improvement Amendments of 1988. The rapid prescreen data was tabulated and compared with data for a similar time period using the laboratory's normal quality assurance program. Seven hundred and twelve cases underwent rapid prescreen. Six hundred and forty-two were interpreted as negative. Twenty-six cases were interpreted as low-grade squamous intraepithelial lesion (LGSIL) or higher. Forty-four cases were classified as needing further review. For the 642 negative cases by rapid prescreening, routine screening reported 537 as negative and 105 as either abnormal or needed cytopathologist review. The error rate for the rapid prescreen is 50 of 712 (7.0%); for LGSIL and above 19 of 712 (2.6%). Of the 105 abnormal cases or those submitted for cytopathologist review, 31 were interpreted as atypical squamous cells of undermined significance (ASCUS), 41 cases as reactive/repair, 17 as LGSIL, 4 as unsatisfactory, 1 as atypical squamous cells, cannot rule out high-grade squamous intraepithelial lesion (ASC-H), 8 as the presence of endometrial cells in a women aged >40, 1 as malignant melanoma, and 2 as within normal limits with the presence of Actinomyces. The laboratory's routine quality assurance program selects cases, 10% of initially interpreted negative cases plus any gynecologic cytology on patients with a prior abnormal cervical cytology, or history of cervical epithelial cell abnormality. This quality assurance program averages 29% of cases, 4,045 of a total of 13,767, in 2008. Thirty-seven (0.9%) cases were detected in this rescreen (ASCUS, 16 cases; LGSIL, 13 cases; 1 high-grade squamous intraepithelial lesion; 4 ASC-H; and 3 atypical glandular cells of undetermined significance). Eliminating ASCUS cases, eight significant cases were detected, with an error rate of 0.2%. In this cytology laboratory, the rapid prescreen did not prove as reliable as routine quality assurance program for cervical cytology cases.

Effectiveness of rapid prescreening and 10% rescreening in liquid-based Papanicolaou testing

Although rapid prescreening (RPS) has been shown to be an effective quality control procedure for detecting false-negative conventional Papanicolaou (Pap) tests, RPS has not been widely implemented in the United States. In our laboratory, cytotechnologists performed RPS in 3,567 liquid-based Pap tests: 1,911 SurePath (BD Diagnostics-TriPath, Burlington, NC) preparations that were manually screened and 1,656 ThinPrep Pap tests (Hologic, Bedford, MA) that were imaged using the ThinPrep Imaging System (Hologic). We compared the sensitivity of RPS, 10% rescreening (R-10%), and routine screening (RS). In contrast with previously published findings, we found that RS + RPS did not improve screening sensitivity compared with RS + R-10%. These results support the following hypotheses: (1) Higher baseline RS sensitivity as a result of Pap test diagnoses standardization implemented for quality improvement purposes decreases the performance impact of RPS. (2) R-10% and RPS quality assurance methods detect diagnostic failures caused by different types of cognitive errors.

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

BACKGROUND

Rapid rescreening (RR) of negative Papanicolaou smears (PS) is used in many countries as a quality-assurance measure. Seeding of abnormal slides has been suggested as a way to increase the sensitivity of this procedure. Since 2004, the authors have carried out RR with seeding before issuing reports. In this article, they describe their experience.

METHODS

Abnormal seeds were sourced from the previous day's high-grade cases, both squamous and glandular. Slides were evaluated for the 'degree of difficulty' (which was defined as the number of fields required to find (fields-to-find [FTF]) the abnormality), relabeled, and redotted to make them indistinguishable from the routine RR work. The number of seeds found/missed, the identity of the screener, the type of seeded abnormality, the degree of difficulty of the seed, and the mapping technique used all were recorded. The cytologists also were surveyed about their views on seeding.

RESULTS

Overall, 14.8% of 3082 high-grade seeds were missed during RR. There was no relation between seeds missed and the mapping technique used. However, the difficulty of the seed was relevant to the number missed and ranged from 8.3% when the FTF was <5 to 36% when the FTF was >10 (P = .000). The difference between intraepithelial seeds and invasive seeds was significant for squamous seeds (P = .031) but not for glandular seeds. Glandular seeds also were more likely to be missed than squamous seeds (23.1% vs 14.3%; P = .002). Most cytologists believed that seeding was a good idea and that seeds increased their level of vigilance.

CONCLUSIONS

The authors' experience demonstrated that routine seeding is practicable for both conventional and liquid-based slides. With the advent of the human papillomavirus vaccine, abnormalities will become rarer, and seeding will be necessary to maintain the alertness of cytologists.

Correlation of cytotechnologists' parameters with their performance in rapid prescreening of papanicolaou smears

BACKGROUND

Efficient quality control is essential to ensure high sensitivity of Papanicolaou (Pap) smears. For this purpose, rescreening of 10% random negative smears is increasingly felt to be ineffective. Rapid rescreening (RR) of all negative Pap smears is more practical and has received widespread acceptance, especially in Europe, although its sensitivity is difficult to monitor and its retrospective nature may influence the vigilance of the screeners. The method of rapid prescreening (RPS) overcomes these drawbacks because rapid review of Pap smears precedes full screening.

METHODS

All routine conventional Pap smears (n = 8364) over 2 months underwent RPS by 12 cytotechnologists, followed by full screening. Data were analyzed to determine correlation between the RPS sensitivity of individual cytotechnologists and both their sensitivity in full screening and their years of experience as cytotechnologists.

RESULTS

There was a striking variability in sensitivity (15.4%-72.7%) among the 12 screeners with an atypical squamous cells of undetermined significance (ASCUS) threshold. There was no correlation between RPS sensitivity of individual cytotechnologists with either their sensitivity in full screening or their years of experience as cytotechnologists.

CONCLUSIONS

The skills required of a cytotechnologist for achieving a high sensitivity in RPS are apparently different from those of full screening and are independent of the sensitivity of the screeners at full screening or of the years of experience as cytotechnologists.

Evaluation of 100% rapid rescreening of negative cervical smears as a quality assurance measure

OBJECTIVE

The objective of this study was to compare the performance of 100% rapid rescreening, 10% random rescreening and the review of smears selected on the basis of clinical criteria, as a method of internal quality control of cervical smears classified as negative during routine screening.

METHODS

A total of 3149 smears were analysed, 173 of which were classified as positive and 2887 as negative, while 89 smears were considered unsatisfactory. The smears classified as negative were submitted to 100% rapid rescreening, 10% random rescreening, and rescreening based on clinical criteria. The rescreening stages were blinded and results were classified according to the Bethesda 2001 terminology. Six cytologists participated in this study, two of whom were responsible for routine screening while the other four alternated in carrying out rescreening so that no individual reviewed the same slide more than once.

RESULTS

The 100% rapid rescreening method identified 92 suspect smears, of which 42 were considered positive at final diagnosis. Of the 289 smears submitted to the 10% rescreening method, four were considered abnormal but only one was confirmed positive in the final diagnosis. Of the 690 smears rescreened on the basis of clinical criteria, 10 were considered abnormal and eight received a positive final diagnosis.

CONCLUSIONS

The 100% rapid rescreening method is more efficient at detecting false-negative results than 10% random rescreening or rescreening on the basis of clinical criteria, and is recommended as an internal quality control method.

Rapid cervicovaginal smear screening: method of quality control and assessing individual cytotechnologist performance

AIM

To validate the method of rapid screening (RS) in the detection of cervical lesions and false-negative results as well as in quality control of cytotechnologist performance.

MATERIAL AND METHODS

The RS method was validated on Papanicolaou-stained and initially conventionally analysed vaginal, cervical and endocervical (VCE) smears collected in an opportunistic programme for the detection of cervical carcinoma. The study included 3680 VCE smears from the Department of Gynaecologic Cytology, University Department of Gynaecology and Obstetrics, Zagreb University Hospital Center, Zagreb and from the Department of Clinical Cytology, Osijek University Hospital, Osijek. Histologically verified abnormal findings accounted for 10% of the study samples. Thirteen cytotechnologists, with no previous experience in RS, performed the test. Each slide was examined using the 'step' technique for 1.5 minutes, the findings were classified as negative or abnormal, and the abnormal ones were also classified according to differential cytological diagnosis. The results were compared with those obtained on initial screening. Abnormal findings from a group of initially negative findings were reanalysed using conventional methods to make definitive cytological diagnosis.

RESULTS

RS yielded a sensitivity of 83.7%, specificity of 93.7%, positive predictive value of 62.4%, negative predictive value of 97.9% and diagnostic accuracy of 92.6%. Relative to the initial abnormal differential cytological diagnosis, the diagnostic value of RS increased with lesion severity [54.8%, 68.0% and 91.3% for cervical intraepithelial neoplasia (CIN) I, CIN II and CIN III respectively]. RS detected 38 additional positive findings; 94.2% of these were atypical squamous cells of undetermined significance (ASCUS)/abnormal glandular cells undetermined significance (AGUS) and CIN I. The rate of additional positive findings was 1.14% (38/3135). The false-negative rate of initial screening was 9.4% (38/406), and individual cytotechnologist sensitivity was 60.0-100.0%.

CONCLUSION

RS could be introduced as an efficient method of quality control to improve the sensitivity of cytological screening as well as for quality control of cytotechnologist performance.

Rapid prescreening of papanicolaou smears

BACKGROUND

Efficient quality control (QC) is essential to ensure high sensitivity of Papanicolaou (Pap) smears. For this purpose, rescreening of 10% random negative smears is ineffective. Rapid rescreening (RR) of all negative Pap smears is more practical and has received widespread acceptance, especially in Europe, although its sensitivity is difficult to monitor and its retrospective nature may influence the vigilance of the screeners. The method of rapid prescreening (RPS) overcomes these drawbacks because rapid review of Pap smears occurs before routine full screening.

METHODS

All routine conventional Pap smears over 2 months underwent RPS by 12 cytotechnologists. Approximately 30 seconds were allowed to prescreen each slide. The presence of abnormal cells (atypical squamous cells of undetermined significance [ASCUS] or above), infection or endometrial cells detected on RPS was documented. All slides subsequently underwent routine full screening. Results of both screening methods were compared.

RESULTS

Of a total of 8364 Pap smears, 310 (3.7%) cases were categorized as abnormal after final diagnosis. Of those, 135 were also detected on RPS (sensitivity of 43.5%). Seventeen abnormal cases were detected only on RPS: these consisted of 13 ASCUS cases, 3 low-grade squamous intraepithelial lesions, and 1 high-grade squamous intraepithelial lesion. The sensitivity of RPS for infections and endometrial cells was 51.6% and 28.3%, respectively. Implementation of RPS did not significantly impact the work flow in our laboratory.

CONCLUSIONS

RPS is an efficient and practical QC tool. It is a reliable method with which to monitor sensitivity and reduce the false-negative rate, and because it is done before finalizing the case, it allows for timely corrections to the diagnosis and avoids the need to amend reports.

Rapid review of liquid-based smears as a quality control measure

The objective of this study was to investigate the effectiveness of a standardized method of rapid review (RR) of monolayer preparations for the identification of abnormalities, the presence of an endocervical component and infectious agents. A total of 200 ThinPrep (Cytyc, Boxborough, MA) slides representing the spectrum of abnormalities commonly encountered in cervical/vaginal cytologic specimens was retrieved from archive. The study set comprised 129 cases within normal limits (WNL); 36 low-grade epithelial abnormalities (LGEA); 28 high-grade epithelial abnormalities (HGEA), including 2 endocervical adenocarcinomas in situ (AIS) and 7 carcinomas. Eighteen false negative (FN) cases were also included for study. Originally missed on initial review, these cases were found to be abnormal on quality control review (17 LGEA; 1 AIS). Commonly encountered infectious agents were represented and included Candida albicans, Trichomonas vaginalis, herpes simplex virus, and Actinomyces. The slides were reviewed using a standardized method of RR (turret technique, for 60 sec) by three experienced screeners masked to the original reference diagnosis. Median sensitivity for LGEA was 70% (range, 67-72%); HGEA, 69% (range, 54-80%); and FN, 65% (range, 56-78%). Specificity remained high, median specificity for LGEA was 95%; HGEA, 97%; and FN, 100%. There was no significant overcalling of any diagnostic category. The chi-square test at P < 0.05 showed no significant difference between RR and full manual rescreen of the ThinPrep smears in this study. While no statistical difference was proven, the sensitivity measurements for all categories of abnormality were moderate due to the high proportion of atypical cases included into the study set. Abnormalities on the monolayer preparations frequently displayed fewer, smaller groups of disaggregated cells with rounded cytoplasmic outlines that were difficult to discern on RR. Interobserver variation was noted. Monolayers with a paucity of diagnostic cells and those displaying subtle nuclear atypia were often overlooked.

[Performance of cervical cytology with review by different observers and hybrid capture II in the diagnosis of cervical intraepithelial neoplasia grades 2 and 3]

To evaluate the performance of initial cervical cytology and that collected at the reference service with a review conducted by different observers and techniques, as well as hybrid capture II, in the diagnosis of high-grade cervical intraepithelial neoplasia (CIN), 105 women attended from August 2000 to June 2001 for preneoplastic atypia upon cervical cytology were included. A new cervical cytology and hybrid capture II for DNA-HPV were conducted in all the patients. Cervical biopsies were taken in 91 women. Performance of the investigative procedures was described by estimating the sensitivity, specificity, and positive likelihood ratio (PLR), with a 95% confidence interval (95% CI), considering histological diagnosis the gold standard.

RESULTS

initial cervical cytology showed sensitivity and specificity of 57% and 82% for diagnosis of CIN grades 2 and 3, with a PLR of 3.2 (95% CI: 1.5-6.8). Referral cervical cytology showed a sensitivity and specificity for CIN 2 and 3 of 79% and 84%, respectively, with a PLR of 5.0 (95% CI: 2.5-10.0). Sensitivity (86%), specificity (80%), and PLR (4.3) were similar when a second observer (using a routine technique) reviewed the slide. Using rapid revision by a third observer, the sensitivity was significantly lower (64%). Hybrid capture II showed a high sensitivity (100%), low specificity (43%), and low PLR (1.7, 95% CI: 1.4-2.2).

One hundred percent thorough quality control rescreening of liquid-based monolayers in cervicovaginal cytopathology

BACKGROUND

Quality control (QC) of Papanicolaou (Pap) smear testing focuses on the identification of screening errors by 10% random, rapid, or thorough manual rescreening of some portion of negative smears. One hundred percent thorough manual rescreening has been reported to be the most effective method of identifying screening errors in conventional Pap smears (CP), but to the authors' knowledge no experience with this QC method has been reported for the ThinPrep Pap test (TP). The current study reports the estimated screening error rate of TP as determined by a QC program using 100% thorough rescreening.

METHODS

All TP samples received at the study institution between January 1, 1999 and December 31, 2000 and initially screened as negative underwent thorough manual QC rescreening.

RESULTS

A total of 53,419 TP samples were received during the study period. Of these, 5,368 cases (10%) initially were interpreted as abnormal. A total of 47,247 cases (88.4%) were rescreened. Abnormalities were identified in 804 additional cases, for a screening error rate of 13.0%. Of the 804 cases, 678 (84.3%) were atypical squamous cells of undetermined significance, 116 (14.4%) were low-grade squamous intraepithelial lesions, and 10 (1.2%) were high-grade squamous intraepithelial lesions. No tumors were identified on rescreening.

CONCLUSIONS

In the current study, 100% thorough rescreening of TP samples was found to result in the detection of a significant number of abnormalities that would have been missed by routine random 10% QC rescreening. The screening error rate determined by 100% thorough QC rescreening of TP is comparable to that reported for CP QC rescreening.

Quality management in gynecologic cytology using interlaboratory comparison

OBJECTIVE

To describe a comprehensive integrated laboratory quality management plan for gynecologic cytology.

DESIGN AND SETTING

Cytopathology laboratory performance monitors with interlaboratory comparison.

RESULTS

Utilizing College of American Pathologists Q-Probes studies, the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology, and other published data, a quality management program for gynecologic cytology involving diagnostic statistics, screening limits and competency assessment, retrospective rescreening, real-time rescreening, cytology-biopsy correlation, follow-up of patients with abnormal cytology results, turnaround time, examination of unknown slides (survey programs), and new technology is described.

CONCLUSION

Regular coordinated monitoring of performance, with longitudinal and interlaboratory comparison utilizing the methods described, provides an opportunity to optimize gynecologic cytology service.