Internal quality assurance in cervical cytology—one laboratory's experience

The results of an internal quality assurance exercise in one cervical cytology laboratory in England are presented, using differing types of partial percentage re-screening of cervical smears. An overall false-negative dyskaryotic rate of up to 4.3% was demonstrated, with the final cytology report diagnosis differing from the primary screening diagnosis in 1.3% of cases. These findings are discussed, with the aim of helping to foster debate on the setting of national laboratory internal quality assurance standards.     

European guidelines for quality assurance in cervical cancer screening: recommendations for cytology laboratories.

The quality of a cervical cytology laboratory depends on adequate handling and staining of the samples, screening and interpretation of the slides and reporting of the results. These guidelines give an overview of procedures recommended in Europe to manage the balance between best patient care possible, laboratory quality assurance and cost effectiveness and will be published as a chapter 4 in the European Guidelines for Quality Assurance in Cervical Cancer Screening. The laboratory guidelines include protocols for personnel and organisation, material requirements, handling and analysing cervical samples, recording of results, quality management and communication. The section on quality management is comprehensive and includes protocols for all aspects of internal and external quality assurance. The guidelines are extensively referenced and as far as possible the recommendations are evidence-based.     

Cervical cytology quality assurance in Washington State.

The objectives of this study were to establish a profile of cervical cytology laboratories in Washington State, identify quality assurance problems amenable to correction through education or legislation, and describe differences between large and small cytology laboratories. All 43 Washington laboratories that perform cervical cytology were surveyed by mail during 1989. Completed surveys were returned by 37 (86%) of the laboratories. Nearly half (43%) of the respondents reported processing less than 10,000 Papanicolaou smears annually. Only one-third (35%) of the respondents reported participating in relevant proficiency programs. A proportion of smaller cytology laboratories were compensating their cytotechnologists on the basis of the number of slides read and allowing Papanicolaou smears to be read outside the confines of the laboratory. The results of this study suggest that cytotechnologists in some larger Washington laboratories have been exceeding work load limits recommended by professional associations. Recent legislation includes regulations that address cervical cytology quality assurance. However, continued efforts will need to be made to encourage voluntary adoption of quality control measures not addressed by this legislation.     

Quality assurance activities of the College of American Pathologists

Since its inception, the College of American Pathologists (CAP) has played a fundamental and pivotal role in the development and execution of quality assurance programs for laboratories. Within the realm of anatomic pathology, operational programs include those in surgical pathology, immunohistochemistry and cytopathology. The emphasis of prior cytopathology programs on cervical cytology has now been expanded to include body fluids and fine needle aspiration material. CAP's role in the expansion of quality assurance programs in cytology may be enhanced in the future by intersociety cooperation with established cytology organizations and will also be influenced by and closely linked to the expansion of its quality assurance programs in surgical pathology. As for the Papanicolaou smear, it can no longer be regarded as the "Cinderella of cytology"; it is in fact the present-day cynosure in the laboratory. In recognition of this, CAP has undertaken efforts to help heighten public awareness about the value of Papanicolaou smear testing and is encouraging women to become more informed about the process involved in the examination of their smears.     

Cervical cancer screening from the public health perspective

Many state health departments have a significant role in cervical cancer screening. Given that role, a group of public health personnel from eight southeastern states drafted a set of questions and quality assurance issues to be discussed with a laboratory under consideration as a contract provider of cytology services. The major points of concern included: (1) quality of laboratory services (accreditation, personnel, facilities and operational and quality control procedures); (2) quality of sampling (including techniques used and the training and monitoring of sample takers); (3) terminology for cytology reporting; and (4) protocols used for diagnostic evaluation of abnormal Papanicolaou smears.     

Development of a technical external quality assurance scheme in non‐gynaecological cytology in UK

Technical external quality assurance (EQA) schemes are well established for histopathology and cervical cytology but, to date, sadly lacking for diagnostic cytology (DC). This timely review redresses the balance by describing the development and evaluation of a technical EQA scheme for DC available to the UK, Europe and beyond.     

External quality assurance for cervical cytology in developing countries. Experience in Peru and Nicaragua

Given interest from the professionals concerned, an external quality assurance scheme for cervical cytology can successfully be introduced in developing countries. This is a very important precondition if screening programs are to be expanded and decreases in mortality from cervical cancer are to occur in developing countries. Nicaragua and Peru have been experimenting with an external quality assurance system adapted from the Scottish and Northern Ireland scheme. It has been received with enthusiasm and acceptance and has helped cytology laboratories in these countries focusing on quality issues. Nevertheless, a successful quality control scheme that is to result in improvements in the quality of professionals' diagnostic skills needs to be accompanied by a remedial program for subperformers.     

Factors contributing to false‐negative and potential false‐negative cytology reports in SurePath™ liquid‐based cervical cytology

N. Gupta, D. John, N. Dudding, J. Crossley and J. H. F. Smith
Factors contributing to false‐negative and potential false‐negative cytology reports in SurePath ? liquid‐based cervical cytology Objectives: The characteristics of false‐negative conventional cervical cytology smears have been well documented, but there is limited literature available for liquid‐based cytology (LBC), especially SurePath? samples. We aimed to assess the characteristics of false‐negative SurePath LBC samples. Methods: Over a period of 5 years, an audit of false‐negative reports in SurePath cervical cytology was undertaken. In a workload of 183, 112 samples, 481 (0.3%) false negatives were identified using two routes: those detected by routine laboratory internal quality control (rapid pre‐screening) (n = 463) and those reported as normal (true false negatives) with concurrent high‐grade cervical histology (n = 18). Ninety‐five false‐negative cases with a subsequent biopsy reported as at least cervical intraepithelial neoplasia grade 2 (CIN2+) were reviewed for a number of different cytomorphological features. Results: Of 95 samples with subsequent CIN2+, 30.5% predominately contained microbiopsies/hyperchromatic crowded cell groups (HCGs), 27.3% sparse dyskarytotic cells, 4.2% pale cell dyskaryosis, 6.3% small dyskaryotic cells; 3.2% were misinterpreted cells, 8.4% contained other distracting cells, 7.4% were low contrast, 5.3% were unexplained and 7.4% were true negatives. The mean number of microbiopsies/HCGs in that category was 4.6. The mean number of abnormal cells in the sparse dyskaryotic cell category was 13.8. Conclusions: Microbiopsies/HCGs were the commonest reason for false negatives. They were usually present in sufficient numbers to be detected but interpretation could be problematic. Dispersed single abnormal cells were usually not identified because of their scarcity or the presence of distracters.     

Rapid pre-screening: a validated quality assurance measure in cervical cytology

We present the results of 3 years' experience of rapid pre-screening in cervical cytology. In our laboratory we rapidly pre-screen all smears. The performance of each primary screener can be assessed. In addition, the relative sensitivity and specificity of each rapid pre-screener can itself be continuously monitored using the final report as a yardstick. In our laboratory individual sensitivity of rapid pre-screening for the detection of high-grade abnormalities was in the range of 44-90% with an overall laboratory sensitivity of 69%. Specificity was in the range of 94-99% with an overall laboratory specificity of 98%. Rapid pre-screening allows checking of the checkers and pathologists and tends to promote uniformity in the assessment of smear adequacy. This form of continuous quality assurance is practical, convenient and acceptable to staff.     

Comparison of SurePath® and ThinPrep® liquid‐based cervical cytology using positive predictive value,atypical predictive value and total predictive value as performance indicators

P. K. Wright, J. Marshall and M. Desai Comparison of SurePath ^® and ThinPrep ^® liquid‐based cervical cytology using positive predictive value, atypical predictive value and total predictive value as performance indicators Objective: Two liquid‐based cytology (LBC) systems are in widespread use in the UK: ThinPrep^® and SurePath^®. A number of studies have now compared LBC with conventional cytology in cervical screening. However, to date, we are aware of no studies that have compared ThinPrep^® with SurePath^® LBC. As the selection and use of specific diagnostic systems in a laboratory has significant clinical and economic implications, there is a clear need to compare directly existing LBC technology. The objective of this study was to compare ThinPrep^® with SurePath^® LBC in a single cytology laboratory using performance indicators. Methods: Data were collected for all cervical cytology samples processed at Manchester Cytology Centre over a 1‐year period. ThinPrep^® LBC was compared with SurePath^® LBC using positive predictive value (PPV), atypical predictive value (APV) and total predictive value (TPV), reflecting outcome of cervical intraepithelial neoplasia (CIN) grade 2 or worse for high‐grade dyskaryosis (PPV), low‐grade dyskaryosis or borderline (atypical) cytology (APV) and all (total) abnormal cytology (TPV). Results: 2287 (out of 56 467) (ThinPrep^®) and 586 (out of 22 824) (SurePath^®) samples showed borderline or worse cytology after exclusion criteria. PPV, APV and TPV were within acceptable ranges for both ThinPrep^® and SurePath^®. Conclusions: ThinPrep^® and SurePath^® were equivalent based on three performance indicators. We suggest that APV and TPV should be used as an adjunct to PPV and other methods of quality assurance for cervical screening.     

Rapid rescreening of cervical smears as a quality control method in a high-risk population

OBJECTIVE: Cancer of the cervix is one of the commonest cancers in South Africa. Accurate cytological diagnosis is one of the prerequisites for an effective cervical screening programme and requires the implementation of appropriate quality assurance modalities. This study was undertaken to determine if rapid review of reportedly negative cervical smears is a useful internal quality assurance modality in an unscreened population with very high rates of cervical carcinoma. METHOD: Approximately 26% of all cervical smears received at the study institution between 1 January 1998 and 31 December 2003, and initially reported as negative or inadequate, underwent rapid review. RESULTS: A total of 62,866 (26%) cervical smears out of 241,796 reportedly negative or inadequate cervical smears underwent rapid review. An amended report was sent out in 373 (0.59%) of these 62,866 cervical smears. This included 101 cases of high-grade squamous intraepithelial lesion (HSIL) and high-grade atypical squamous cells (ASC-H), 143 low-grade squamous intraepithelial lesions, 54 atypical squamous cells of undetermined significance (ASC-US) and 33 atypical glandular cells that were not reported initially. The false-negative proportion for HSIL and ASC-H (combined) in this study was 5.76%. No squamous cell carcinomas were diagnosed on rapid review but one patient with HSIL/ASC-H on review had squamous cell carcinoma on biopsy. Three cytotechnologists had a lower sensitivity of primary screening and required retraining. CONCLUSIONS: Rapid review is beneficial as an internal quality assurance modality in an unscreened high-risk population and increases the detection of women with significant cervical lesions requiring treatment. The relatively low cost of rapid review compared with other rescreening modalities makes this an attractive option in low resource settings.     

Quality control in cervicovaginal cytology by cytohistological correlation

N. Izadi‐Mood, S. Sarmadi and S. Sanii
Quality control in cervicovaginal cytology by cytohistological correlation Objective: Frequent studies attest to the correlation of cytological interpretations with defined histopathological entities. Nevertheless, as part of quality control, cytology laboratories are required to compare Papanicolaou smear reports with those of cervical biopsies to search for discrepancies. We have attempted to determine and categorize the causes of existing discrepancies in our laboratory in order to clarify the source of errors. Methods: We reviewed 670 cervical smears that were paired with subsequent punch biopsy or endocervical curettage samples, obtained within 2 months of the cytology, and found out that 60 smear‐biopsy pairs were discrepant regarding the diagnosis. These cases were categorized into four error groups after careful re‐evaluation of the original smear and biopsy slides. Results: In 51 (85%) of 60 cervical smear‐biopsy pairs with reports that disagreed, the initial diagnoses of both cervical smear and biopsy were confirmed by the review opinion; in these cases, cytology and biopsy ‘sampling errors’ were responsible for 40 and 11 instances of discrepancy, respectively. Seven cases (11.1%) were discrepant due to ‘smear interpretation errors’ and consisted of five cases with initial under‐diagnosis and two cases with initial over‐diagnosis. One case (1.7%) was due to ‘screener error’. In another case, discordance was due to cervical ‘biopsy interpretation error’, with initial over‐diagnosis as squamous intraepithelial lesion. Conclusion: In this retrospective study, we determined the causes of cytohistological discrepancies in cervical samples. The main explanation for discrepancy was ‘sampling error’.     

Screening for the prevention of cervical cancer in the era of human papillomavirus vaccination: an Australian perspective

Australia has a unique and highly successful screening program for cervical cancer which is based on the conventional Pap smear. Since its introduction in 1991 there has been a decline in both the incidence of and mortality from this disease. Part of the success of this program has been the introduction of Pap test registers and strict quality assurance measures for cervical cytology, including compulsory key performance indicators for laboratories. Using these measures, nationwide calculations give cervical cytology in Australia a sensitivity of 78% for high-grade lesions and a positive predictive value (PPV) of 78%. Australia was the first country to introduce a widespread government-funded human papillomavirus (HPV) vaccination program in 2007. Because of the high accuracy of Australian cytology, HPV testing alone, given its low PPV and high cost, is unlikely to be a viable alternative to cytology for primary screening in this country. Australia therefore faces unique issues and choices in integrating its extensive vaccination program with a successful cervical screening program.     

Ensuring quality in cervical screening programmes based on molecular human papillomavirus testing

The increased use of human papillomavirus testing within cervical screening programmes necessarily brings about changes to the laboratory services required to support them. A crucial element of such services is to demonstrate initial and ongoing quality of the test (and associated processes). In this review, we outline some of the quality considerations and challenges with an emphasis on the laboratory including assay and platform validation, internal quality control selection and strengths and weaknesses of external quality assurance schemes. The influence and role of key external entities, including regulatory agencies, guideline groups, programme commissioners and commercial providers, are also discussed.     

Quality assurance in cytopathology. Recommendations and ongoing quality assurance activities of the American Society of Clinical Pathologists

The recommendations and activities of the American Society of Clinical Pathologists (ASCP) pertaining to quality assurance in cytopathology are reviewed. To assure the early detection of cervical cancer, the ASCP recommends that all women who are, or have been, sexually active should have an annual Papanicolaou smear examination, the reasons for which are discussed. To assure the optimal quality in the evaluation of these smears, the ASCP recommends that the screening should be performed (1) in an accredited laboratory by certified cytotechnologists, (2) for whom realistic workloads have been established, (3) under the supervision of a pathologist adequately trained in cytology, (4) who will maintain an ongoing quality assurance program. In addition, (5) Papanicolaou smear evaluations should be available to all patients at a reasonable cost and (6) the financial incentives for the performance of low-quality screening should be eliminated. The society's quality assurance activities discussed include the Check Sample program, self-assessment examinations, meetings and publications; planned additions to this arena include a challenge exam and proficiency survey mechanisms.     

Ethical problems in cytology

Great advances in medical science have raised a number of ethical issues, many of which affect cytopathology. Some of the main issues addressed in this paper relate to the organization of a cytology laboratory: internal and external quality control, adequate staffing levels and staff education, cytopathology reporting format and contents, confidentiality issues, relationship with the clinicians and involvement of cytopathologists in clinical management teams. Quality control has to be provided within cytology departments but external quality assurance is also essential, with national monitoring. New technologies should be used according to the best scientific methods, following cytological analysis. Scientific work in cytology has to respect the general principles of scientific ethics. The patient's interest has to be the main reason for such work.     

Inflammatory atypia and the false-negative smear in cervical intraepithelial neoplasia

The effectiveness of cervical cytologic screening is compromised by the increasingly recognized prevalence of false-negative smears. Our previous studies suggested that some false-negative cytologies can be accounted for by smears showing cervical intraepithelial neoplasia (CIN) reported as inflammatory atypia; we found that at least 4% of 5,752 consecutive smears had been underreported in this manner. In the present study, that data was reanalyzed to derive 95% confidence limits for the number of CIN smears reported as inflammatory atypia. Using several differing estimates of cytologic screening sensitivity, it is speculated that, under certain testable assumptions, colposcopy of patients with cytologic diagnoses of inflammatory atypia may be one cost-effective approach to finding CIN cases missed by screening. If confirmed, these findings imply that laboratory quality assurance efforts, traditionally directed to the most serious cytologic diagnoses, should also focus in part on nondysplastic atypia.     

Toward implementation of a regional quality assurance program in cytopathology: the Hong Kong experience

OBJECTIVE: To develop a local quality assurance program in cytopathology based on circulation of patient specimens on glass slides, with limited resources. STUDY DESIGN: A working group was set up for design and running of the program. Participation is on a laboratory basis. The scope and frequency of testing are defined. Well-documented cases (including gynecologic, nongynecologic and fine needle aspiration cytology) with commonly encountered diagnoses are collected. Consensus concerning the diagnosis, interpretive menu and scoring system is sought before the actual slide circulations using express mail. After returning their answers to the program organizer, the participating laboratories receive immediate feedback on their scores, with reference answers, explanatory notes, "whole-mount" images of glass slides and cumulative responses of peer laboratories for on-site checking. At the end of each year, an electronic file containing representative photomicrographs of all cases examined is provided to individual laboratories for their permanent records and training purposes. RESULTS: The program was launched in mid-2003. There were 24 and 27 participating laboratories from Hong Kong (and Macau) in 2003 and 2004, respectively. To date, >150 well-documented cytology cases are available in the slide pool and ready for circulation. As the revenue is mainly to cover the expenses of express mail, the program can be carried out at a relatively low cost. CONCLUSION: In order to have any cytology quality assurance program accepted by local laboratories, it has to be fair and practical. Strict confidentiality needs to be observed throughout the process. This program emphasizes both performance assessment and educational value. Adequate representation from experienced local cytology workers, detailed documentation support from authorities and assistance from dedicated staff are essential to the success of any external proficiency testing scheme. Regular review and evaluation are also necessary for continuous improvement. The Hong Kong experience can serve as an example of running a glass slide-based cytology quality assurance program in a small region with limited resources.     

Laboratory performance measures: evidence against low-risk women explaining low detection rates of high-grade abnormalities

OBJECTIVE: When a laboratory has a low reporting rate of high-grade abnormality for its cervical cytology specimens, the question arises whether this is due to the laboratory screening a low-risk group of women. This study was undertaken to explore the hypothesis that a low-risk group of women were screened by Victorian laboratories not meeting the recommended minimum standard for the detection of high-grade abnormalities. METHODS: A cohort of 28 094 women was established comprising women whose cervical cytology was reported in 2000 by laboratories not meeting the recommended standard of 0.5% high-grade abnormalities in their reporting of community smears. Outcome measures included the prevalence of high-grade abnormality on the next cytology test for the women, the positive predictive value of the cytology reports of high-grade abnormality, and the standardized incidence ratio for a later diagnosis of cervical cancer. RESULTS: The prevalence of high-grade abnormality was 0.36% on the index cytology compared with 0.68% on the first subsequent cytology report. Sixty-nine per cent (60/87) of the index cytology reports of high-grade abnormality were confirmed as high-grade abnormalities on histology, compared with 70.8% (121/171) for the first subsequent reports of high-grade abnormality. During 70 015 person-years at risk, nine cases of cervical cancer were observed compared with 5.21 expected cases, giving a standardized incidence ratio of 1.73 (95% CI 0.79-3.28). CONCLUSIONS: These results do not support a hypothesis that the low detection rate for high-grade abnormalities is due to the women comprising a low-risk group for cervical neoplasia.     

Cytopathology in Slovenia

Cytopathology started in Slovenia in the early 50s with exfoliative cytology, while fine needle aspiration biopsy (FNAB) was introduced some 10 years later. Today cytopathology is a well accepted diagnostic method in Slovenia and there are currently 20 cytopathological laboratories and 17 cytopathologists. The number of specimens examined in 2001 was 26 230 FNABs, 13 355 exfoliative non cervical and 323 888 cervical smears. FNABs are performed by cytopathologists, by clinical doctors and by radiologists. So far only the cytopathologists have a supervised training period in performing biopsies. In future the same requirement will be obligatory for non pathologists. In four laboratories immunocytochemistry is used as an ancillary technique to morphology and one laboratory is using also flow cytometry for immunophenotyping of lymphomas. The classification system used in Slovenia for reporting the findings in cervical cytology is a combination of Papanicolaou's classification and assessment of dyskariosis. In spite of a long tradition in opportunistic screening for cervical cancer (Cca) an organised screening programme was started late. A four year pilot study, which included one third of the women population of Slovenia, was concluded in 2002 and an organised screening programme was introduced to the whole country in 2003. The incidence rate of Cca in Slovenia has been rising slowly since 1994 and it reached 19.6/100 000 in the year 2000. The mortality rate has remained roughly constant at 5-7/100 000 for the last 20 years. During the last few years quality assurance measures have been taken for improving the performance in cervical cytology.