Control specimens for immunocytochemistry in liquid‐based cytology

T. Hansen, H. Pedersen, V. Brauner and J. Hariri Control specimens for immunocytochemistry in liquid‐based cytology Objective Immunostaining necessitates the use of positive as well as negative controls, which is usually an easy procedure in immunohistochemistry (IHC). To find suitable control specimens for immunocytochemistry (ICC) is, on the other hand, a challenging task and to the best of our knowledge is not sufficiently dealt with in the English literature. The aim of this trial was to develop an applicable method to select, collect, process and store control specimens for ICC using liquid‐based cytology (LBC). Methods The study included 21 different antibodies, which were known to react with at least one of the cellular components from tonsils, serous fluids and bronchial washings. The LBC specimens from the tonsils were collected as SurePath? specimens (BD, Bencton, Dickinson and Company) by brushing the cut‐surface of a fresh tonsil and then immersing the brush head into the SurePath? vial. The serous fluids and bronchial washings were fixed in CytoRich Red? (BD). Some of the cellular suspensions from the tonsils and equal amounts of the serous fluid and the bronchial washings were also mixed as a cocktail. Unstained SurePath slides were then prepared on the PrepStain? (BD) Non‐GYN Program, and the unstained and dry slides were then stored at 5 °C to test the effect of storage on the preservation of the antigenicity. ICC was then performed on BenchMark‐XT?. Results Cellular components in unstained SurePath? slides reacted positively with relevant antibodies. Slides that were stored for up to 40 days did not loose staining intensity. Conclusion Specimens from body fluids and cell‐suspensions that are collected by brushing the cut‐surface from different types of fresh tissues or organs can be used as control specimens either separately or as mixtures. Dry and unstained slides can then be prepared and stored in a refrigerator for at least 40 days without loosing staining intensity.     

P-9A COMPARISON OF THE REPORTING MORPHOLOGICAL FEATURES OF GLANDULAR NEOPLASIA FOR CONVENTIONAL AND LIQUID BASED CYTOLOGY FOR CERVICAL SAMPLES

Cervical cancer accounts for approximately 15% of cancer diagnosed in women worldwide with up to 190 000 deaths per annum. One of the major causes of cervical cancer is the infection of human papillomavirus (HPV), a DNA virus. This virus is epidermotropic; there are over 75 subtypes and subtypes 16, 18, 31 and 33 are associated with cervical intraepithelial neoplasia (CIN) and carcinomas. Since the start of the cervical screening in mid 1960s, the cervical cancer rate has decreased. There are two techniques used for slide preparation and staining: conventional cytology and liquid based cytology (LBC). Due to the differences in sample collection and preparation, certain aspects of cell morphology, architecture and patterns will present differently from each other on the slide. The study was conducted in a County Hospital. Twenty conventional slides and eight LBC slides already reported as ? Glandular neoplasia were reviewed and assessed with regards to their morphological features. Moreover, conventional slides were compared with LBC slides to determine the differences in their cell morphology, sensitivity and specificity. Furthermore, a semi-quantitative method was used and also true-positive and false-positive rates were evaluated using positive predictive value (PPV). The findings indicated that despite the differences in cell morphology there are many similarities between the two techniques. The study also showed that it was difficult to distinguish between abnormal glandular cells and abnormal squamous cells, which may end in a false positive result and over reporting of glandular neoplasia. Finally, it showed that LBC slides were easier to screen and also had a higher positive predictive value (PPV) resulting in higher sensitivity and specificity. In conclusion, the LBC technique is more accurate and conversion to this technique is the positive step in the screening program.     

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.     

O-5UNIDIRECTIONAL VERSUS BIDIRECTIONAL SCREENING OF SUREPATH® LIQUID BASED CYTOLOGY SLIDES –PITFALLS & PERILS OF STUDY DESIGN

Although the characteristics of false negative conventional smears have been well documented there is limited literature available for Liquid Based Cytology (LBC), especially with regard to SurePath ™ samples. We will present the results of a 16 month audit and describe the typical characteristics of false negative cases in a medium sized screening laboratory processing approximately 42 000 samples per annum. Cases were identified either from routine rapid screening or by review of negative samples from women with a known high grade CIN lesion. 153 cases were identified: 149 by rapid screening, the remainder by review of the negative samples from women with known CIN. Of those identified by rapid screening 123 were reported as borderline nuclear change, 11 as mild, 4 as moderate, 8 as severe and 3 as CGIN. Only those cases that were found to have a histological lesion were used in the study ( n  = 27): Twenty-three were identified by rapid review and a 4 by review of previous negative samples. Six were found to have CIN 1, 7 CIN 2, 13 CIN 3 and 1 CGIN. Examples of the typical characteristics will be demonstrated. Features similar to those observed in conventional smears were identified; scanty abnormal cells (less than 30 per preparation), low contrast samples, pale cells and microbiopsies. In contrast to conventional smears, missed abnormal cells were almost always uniformly scattered throughout the sample.     

Personal view. Is it reality or an illusion that liquid‐based cytology is better than conventional cervical smears?

Liquid-based cytology (LBC) has been heralded as the way forward for cervical screening, and as the answer to many of its problems. It is already used as a sole method of cell preparation in many private clinics in the UK. It is being used for colposcopy smears in many NHS clinics and is now being piloted for primary screening in three screening centres in England, as well as one in Scotland and one in Wales. LBC has been welcomed as a new technology because it deals with the problem of specimen adequacy at source, removing responsibility for slide preparation and fixation from the clinician or nurse. It provides uniformly well-fixed preparations that are free of inflammatory exudate and blood, and seem easier to screen than conventional smears. There are many articles in the world literature suggesting that LBC is more accurate than conventional screening, and it is thought likely to reduce the number of false negative tests. The main reasons for piloting LBC in the NHS Cervical Screening Programme (NHSCSP) lie in its potential for reducing screening times and for reducing the numbers of repeats for inadequate tests. LBC is expensive in terms of equipment, capital costs, maintenance, consumables, training, technical preparation time, transportation and disposal of liquid media. Its costs could be justified if they were offset by the money saved from reduced screening time and repeat tests, but only if its accuracy in terms of sensitivity and specificity were proven to be equal to or better than conventional cytology. Although that is generally held to be true by the public and medical profession alike, there is very little hard evidence to support it.     

Conventional Pap smear and liquid-based cytology as screening tools in low-resource settings in Latin America: experience of the Latin American screening study

OBJECTIVE: To evaluate the performance of the conventional Pap test and liquid-based cytology (LBC) in an ongoing multicenter trial testing optional screening tools (cytology, screening colposcopy, visual inspection with acetic acid, visual inspection with Lugol's Iodine, cervicography and Hybrid Capture II [HCII] (Digene Brazil, S?o Paulo, Brazil) conventional and self-sampling), for cervical cancer in Brazil and Argentina. STUDY DESIGN: A cohort of 12,107 women attending four clinics (Campinas, S?o Paulo, Porto Alegre, Buenos Aires) were randomized into the 8 diagnostic arms. Women testing positive with any of the tests were referred for colposcopy, and cervical biopsies were used as the gold standard to assess performance characteristics of the diagnostic tests. Conventional Pap smears were sampled by all clinics (n = 10,240), and LBC (Autocyte PREP, [TriPath Imaging, Burlington, North Carolina, U.S.A.], n=320, and DNA-Citoliq [Digene Brazil], n =1,346) was performed by 1 of the clinics. RESULTS: Conventional Pap smears showed no squamous intraepithelial lesions (normal) in 8,946 (87.4%) and LBC in 1,373 (82.4%). Using high grade squamous intraepithelial lesions (HSIL) as the cutoff, Pap smears predicted high grade (cervical intraepithelial neoplasia [CIN] 3) with OR 63.0 (95% CI, 36.90-107.70), standard error (SE) 59%, SP 97.8%, positive predictive value (PPV) 68.1% and negative predictive value (NPV) 96.7%. The same figures for Autocyte PREP were: OR 9.0 (95% CI, 2.43-33.24), sensitivity (SE) 33.3%, specificity (SP) 100%, PPV 100% and negative PV (NPV) 88.8%. DNA-Citoliq detected CIN 3 as follows: OR 11.8 (95% CI 2.60-53.26), SE 40.0%, SP 94.6%, PPV 40.0% and NPV 94.6%. Lowering the cutoff to low grade squamous intraepithelial lesions increased SE and NPV but compromised SP and PPV. The detection rates for high grade lesions after an atypical squamous cells of undetermined significance diagnosis were similar with the 3 techniques. In our settings, the 3 methods of cervical cytology were slightly different in performance. The conventional Pap smear had the highest SE, while Autocyte PREP had 100% SP and PPV in detecting CIN3 with the HSIL cutoff. All 3 tests had lower SE but higher SP as compared to HCII.     

Flow cytometric analysis and cytopathology of body cavity fluids

A total of 75 samples of body cavity fluids from 71 patients were analyzed by both flow cytometry (FCM), to detect cells with an abnormal DNA content (aneuploidy), and by conventional cytopathology. Samples included 27 pleural fluids, 35 peritoneal fluids, 11 peritoneal washings and 2 pericardial fluids. For cytologic examination, the samples were prepared using standard techniques. Samples for FCM analysis were centrifuged and exposed to a hypotonic solution containing detergent and propidium iodide, a DNA intercalating fluorescent stain. Aneuploidy as well as cytologic malignancy were found in 17 samples. Forty-seven samples had normal DNA histograms by FCM and were also cytologically negative. Four samples suspicious by cytology but normal by FCM were from patients with renal-cell carcinoma (two samples from the same patient), endometrial adenocarcinoma without metastasis and chronic lymphocytic leukemia. Three samples abnormal by FCM but negative by cytology were from patients with ovarian cystadenoma, cirrhosis and uterine leiomyoma. FCM showed aneuploidy in four cytologically negative samples from patients with histologically proven malignancy (lymphoma, colonic adenocarcinoma, cervical squamous cell carcinoma, and endometrial adenosquamous carcinoma). Based on these results, FCM analysis combined with conventional cytopathology yielded 100% sensitivity, 100% predictive value of a negative result and 94% specificity. This rapid and quantitative FCM analysis of body cavity fluids can be a very useful adjunct to conventional diagnostic cytopathology.     

Diagnosis of T-cell lymphoma in body fluids: cytologic features and unusual flow cytometric findings

OBJECTIVE: To demonstrate the unique morphologic and phenotypic features observed in cases of T-cell lymphomas presenting as effusions. STUDY DESIGN: Cytologic slides and flow cytometric histograms of 8 cases of body fluids with T-cell lymphoma were retrospectively reviewed. Morphologic features, flow cytometric histograms and immunophenotypes of the cells were evaluated. RESULTS: Three of the 8 cases showed 1 or more of the following: intermediate-to-large cells with an increased nuclear-cytoplasmic ratio, finely granular or vacuolated cytoplasm and round or convoluted vesicular nuclei with a prominent single or multiple nucleoli. Flow cytometric studies of these 3 cases showed an abnormal scatter pattern in the myelomonocytic region of the histograms. Phenotypic analysis revealed variable expression of a T-cell phenotype. The remaining cases showed the conventional morphologic and flow cytometric features of a T-cell lymphoma. CONCLUSION: Morphologic alterations of neoplastic T-cells in body fluids can result in a variety of potentially incorrect diagnoses. The unusual flow cytometric histogram can serve as a useful clue for the diagnosis of T-cell lymphoma in body fluids but could be a potential pitfall for a false negative. Detailed cytologic evaluation combined with flow cytometric study can improve diagnostic accuracy.     

Application of liquid-based preparation to fine needle aspiration cytology in breast cancer

OBJECTIVE: To examine the performance of liquid-based cytology (LBC) in breast cytology to confirm the diagnosis of carcinoma. STUDY DESIGN: Using cell clusters directly scratched from surgically removed tumor masses, we examined the immunocytochemistry, molecular biology and cytomorphology of the specimens. RESULTS: LBC was very useful for gene analysis and evaluating the immunocytochemistry. The cytologic features of LBC were slightly different from those ofa conventional aspiration cytology smear. CONCLUSION: LBC is a promising method for improving the standardization ofpreparations in breast cytology, although care should be taken to account for its characteristic cytologic features. The quantitative analysis of HER-2 mRNA correlated with the results of immunohistochemistry.     

The role of DNA flow and image cytometry in the evaluation of body cavity fluids

In addition to conventional cytomorphologic study, 50 body cavity fluid specimens (benign and malignant) were analyzed by both flow cytometry (FCM) and image cytometry (ICM) in order to evaluate the potential application of these techniques in the diagnosis of malignancy. While 88% of the fluids were similarly classified by FCM and ICM as being either diploid (66%) or nondiploid (22%), with similar DNA index values, nondiploid peaks were identified by ICM alone in 12% of the fluids. Aneuploid populations were present in 92% of the cytologically positive fluids and in 15% of the cytologically negative fluids. All of the latter fluids came from patients who clinically had tumors involving the respective body cavities. These results show that (1) both FCM and ICM are useful adjuvant techniques in the evaluation of body cavity fluid specimens and (2) ICM is superior to FCM in the identification of small aneuploid subpopulations. The identification of aneuploid populations by either method is highly suggestive of malignancy.     

Assessing the wellbeing of cytoscreeners: experience in two NHS cytology laboratories

OBJECTIVE: Cervical screening programmes in England are in transition as the liquid-based cytology (LBC) method replaces conventional Papanicolaou screening and staff in NHS laboratories are trained to analyse LBC smears. Cytoscreeners and biomedical scientists undertake routine microscopy of slides, but the scientists usually have a wider professional role. Attitudinal surveys were carried out in laboratories where LBC was partially introduced. METHODS: Staff in two cytology laboratories in Greater Manchester were surveyed twice over 6 months. The questionnaire assessed work pressures using scales from the Measures of Work Characteristics instrument, work-related stress using the General Survey version of the Maslach Burnout Inventory, job intentions and job satisfaction. RESULTS: Cytoscreeners, many aged over 50 years, formed over 60% of respondents in both surveys (27/42 in the first survey), and biomedical scientists and doctors, 30%. Both groups were under moderate pressure from work demands in each survey, but cytoscreeners had significantly less autonomy over their working methods (P < 0.001). Although both groups experienced similar levels of exhaustion, cytoscreeners were much more cynical or indifferent towards work in the second survey (P = 0.008) and had lower expectations of being effective (P < 0.001). For the cytoscreeners, there were strong negative correlations in both surveys between cynicism and the work characteristics of influencing decisions and autonomy/control. CONCLUSIONS: The strength of the relationship between work performance and wellbeing serves to emphasize the importance of the new LBC technology in ameliorating low morale where it exists. Further attitudinal research involving larger samples of laboratories is warranted to assess the full impact of this innovation.     

P-6SCREENER SENSITIVITY – ALL CHANGE FOR LBC

Introduction:  This poster aims to provide a discussion point for the calculation of screener performance. LBC has brought about changes in the way slides are interpreted, single dispersed isolated dyskaryotic cells take on a new meaning and the process of quality control, rapid review has changed. These changes challenge the rationale behind screener sensitivity calculations especially as many laboratories are in an early learning phase with regard to LBC.
Method:  Screener sensitivities and the PPV of reporting consultants for a period of six months post LBC conversion are compared with those since the introduction of LBC.
Results:  Screener sensitivities have dropped below the 95% threshold for high-grade dyskaryosis.
Discussion:  The change in rapid review or preview from a partial stepped rescreening of a conventional smear to a full rescreening of LBC slides has meant that all missed abnormalities that may not have been visualised in the conventional slide have a greater possibility of detection in the LBC slide. In analysing screener sensitivity a holistic approach that assesses the reasons for missing or misdiagnosing high-grade abnormalities is advised. Over reporting by consultants as indicated by PPV and slide review should be taken into account when there is a suspected poor performer. The recent move to refer all mild dyskaryotic smears for colposcopic assessment and the EQA requirement for screeners to detect dyskaryosis without the necessity for grading suggests that there may be a need to reassess the basis of current screener sensitivity calculations.     

Comparison of the conventional cervical smear and liquid-based cytology: results of a controlled, prospective study in the Abruzzo Region of Italy

OBJECTIVE: To compare conventional cervical testing (CCT) and liquid-based cytology (LBC) within a randomized trial performed during 2001-2002 in the Abruzzo Region of Italy, including a cost-outcome comparative analysis. STUDY DESIGN: Study subjects were recruited in the framework of a controlled, randomized study organized in the Abruzzo Region. Women aged 2 6-64 years were randomized to an active arm (LBC) or control arm (CC1). The particip ating laboratories had no previous ex perience with LBC. RESULTS: The inadequacy rate was 4.3% in CCT and 1.3% in the LBC arm (D < 0.001). Atypical squamous cells of undetermined sign ifi cance and atypical glands of undetermined significance reports were more frequent at CCT vs. LBC. A small, insignificant excess of low grade squamous intraepithelial lesions or high grade squamous epithelial lesions+ reports was observed in the LBC arm. The cervical intraepithelial neoplasia 2+ (CIN2+) detection rate was not statistically different in the 2 arms (CCT=0.54%, LBC= 0.66%, p = 0.28). In the overall series positive predictive value was slightly but not significantly higher in the LBC arm. LBC increased costs by 4.2% per both screened women and CIN2+ detected. CONCLUSION: The study reflects the introductory phase of LBC in laboratories without prior LBC experience. In this setting LBC reduced the inadequacy rate and decreased reading and was at least as sensitive as and more specific than CCT. Utilization of LBC in organized screening programs will be based on local feasibility, considering that the high cost of LBC is only partially compensated for by other benefits, such as residual cellular material, available for molecular testing, including human papillomavirus testing.     

Liquid-based cytology can improve efficiency of cervical smear readers: evidence from timing surveys in two NHS cytology laboratories

OBJECTIVE: Cervical screening programmes in England and Wales were advised by the National Institute for Clinical Excellence in 2003 to adopt liquid-based cytology (LBC) in place of conventional Papanicolaou (Pap) cytology to facilitate laboratory efficiency. Pilot evaluations in England and Scotland monitored daily or weekly workloads of smear readers and concluded that LBC could increase hourly throughput rates. This study, instead, used timing surveys to determine screening rates. METHODS: Two National Health Service cytology laboratories in Manchester and Stockport were partially converted to the LBC ThinPrep process for a cervical screening trial. Three 1-week timing surveys were conducted over 7 months. The surveys covered all LBC-trained staff. The first survey in Manchester also covered staff undertaking conventional Pap screening. The smear readers used timers to record time taken for examining and reporting each slide. RESULTS: In Manchester, in the first survey, nearly 1 minute per slide was saved by the LBC method during primary microscopy. In both laboratories, the mean microscopy time for primary screening of LBC slides was reduced by almost 1 minute between the first and second surveys. There was no difference between the second and third surveys. Microscopy by cytopathologists was also 1 minute per slide quicker with LBC than conventional Pap. The LBC inadequate rates for both laboratories were <2.0%. Organizational factors impacted on the hourly LBC primary screening rates in the laboratories, the rate for Stockport being higher than the rates in the pilot evaluations. CONCLUSIONS: The timing surveys confirm that the LBC ThinPrep technology can improve laboratory efficiency. However, decision-makers should also consider the overall costs and benefits of introducing the technology in screening programmes, including the capital investment and workforce implications.     

Utility of p16(ink4a) immunocytochemistry in liquid-based cytology specimens from women treated for high-grade squamous intraepithelial lesions

OBJECTIVE: To examine whether p16(ink4a) immunocytochemical (ICC) expression detected intraepithelial disease in liquid-based cytology (LBC) specimens from women with high-grade squamous intraepithelial lesions (HSIL), whose specimen was labeled negative for intraepithelial lesion or malignany (NILM). STUDY DESIGN: Residual LBC specimens from women treated for HSIL (n = 21), whose LBC test was interpreted as NILM including marked benign inflammatory changes (BCC) were used. The control (n = 25) consisted of residual LBC specimens from women with documented HSIL. ICC for p16p(16k4a) was performed on a second ThinPrep (ThinPrep 2000, Cylyl Corporation, Boxborough, Massachusetts, U.S.A.) preparation; the percentage ofpositive cells and intensity of immunostaining were recorded. Standard LBC preparations for p16(ink4a) ICC-positive and ICC-negative control cases were reviewed. RESULTS: Twenty-four of 25 (96%) of the HSIL control group were ICC p16(ink4a) positive. In the NILM/BCC group, 2 of 21 with adequate LBC residua were ICC p16(ink4a) positive; on review both were reclassified as epithelial abnormality--1 HSIL and 1 atypical squamous cells cannot exclude HSIL. In both, subsequent colposcopic biopsy yielded HSIL. CONCLUSION: p16(ink4a) ICC positivity on NILM/BCC LBC residua from patients with HSIL may identify cases that merit cytologic review and possible reclassification. The utility of p16(ink4a) ICC in this situation requires further study.     

Is a liquid‐based cytology more sensitive than a conventional Pap smear?

K. Sigurdsson
Is a liquid‐based cytology more sensitive than a conventional Pap smear? Background: The comparative sensitivity of liquid‐based cytology (LBC) test and conventional Papanicolaou (Pap) smears is controversial. Material and methods: This study analyses the distribution of cytology, histology, colposcopy and large loop excision of the transformation zone among women screened in Iceland with LBC at the Cancer Detection Clinic in Reykjavik and with a conventional Pap smear outside the Detection Clinic in 2007–2011. The study material included 42 654 LBC tests from 20 439 women and 103 909 Pap smears from 61 574 women. The period 2000–2004 is used to correct for potential bias as a result of unequal distribution of the studied parameters between the study sites before the introduction of LBC. Results: The observed results indicated that women screened with an LBC sample had significantly decreased detection rates of inadequate smears, increased detection of low‐grade squamous intraepithelial lesion (LSIL)/atypical cytology and referrals to colposcopy, and an increased detection rate of cervical intraepithelial neoplasia grade 2 or worse (CIN2+) irrespective of age. LBC increased significantly the detection rates of high‐grade squamous intraepithelial lesion or worse (HSIL+) cytology and CIN3+ histology only in women under 40 years of age. Taking into consideration the unequal prevalence of the studied parameters between the study sites in 2000–2004 indicated, however, that LBC only affected the rate of inadequate and low‐grade cytology tests under the age of 40 years. Positive predictive values for CIN2+ were not significantly different between the tests. Conclusions: The study results support the view that LBC is no more sensitive than Pap smears for the detection of HSIL+ and CIN2+ irrespective of age. LBC decreased the rate of inadequate smears, but increased the rate of low‐grade cytology under the age of 40 years and decreased the total rate of abnormal smears over the age of 40 years.     

Follow-up study of atypical glandular cells in gynecologic cytology using conventional Pap smears and liquid-based preparations: impact of the Bethesda System 2001

OBJECTIVE: This study evaluated the impact of the Bethesda System (TBS) 2001 in reporting of atypical glandular cells (AGC) when using conventional Pap smears (CS) and liquid-based cytology preparations (LBC). STUDY DESIGN: Follow-up information for all atypical glandular cells of undetermined significance (AGUS)/ AGC cases encountered in Queen Mary Hospital from July 2000 to June 2004 was analyzed. The difference in percentages associated with certain end points when using different reporting systems and preparation methods were compared. The age trends and time interval between cytologic diagnosis and detection of positive end points were studied. RESULTS: More than half of these cases turned out to be "negative." The majority with "negative" end points belonged to the "not otherwise specified" (NOS) groups (including atypical endometrial cells) in TBS 2001. The connotation of "favor neoplastic" carried a high positive predictive value for significant lesions. Most of the significant outcomes were discovered within the subsequent 6 months. A decreased reporting of "AGC, NOS" and an increased reporting of "atypical endocervical cells, NOS" were noted when using LBC. CONCLUSION: Subcategorization of AGC in TBS 2001 according to cellular origin and risk of malignancy, which is further enhanced by application of LBC, is useful.     

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.