Should the laboratory assess the sampling adequacy of cervical smears?

Should the laboratory assess the sampling adequacy of cervical smears? The results of a questionnaire answered by 14 out of the 18 NHS laboratories in Scotland reporting cervical smears showed that, since the publication of Guidelines for Judging the Adequacy of a Cervical Smear, by the British Society for Clinical Cytology (BSCC), rates of unsatisfactory smears had risen from a mean of 3.3% to 6.5%, with some laboratories reporting rates of over 10%. Four laboratories followed the guidelines closely in requiring the presence of two indicators of sampling of the transformation zone, i.e. endocervical cells, metaplastic cells or endocervical mucus. Seven laboratories required one indicator either in all smears or in a subset, whilst three did not require any indicator at all. The laboratories observing the guidelines closely had a higher mean unsatisfactory rate than those partially observing them. The main impediment to the full implementation of the BSCC guidelines appeared to be fear of an unmanageably high unsatisfactory smear rate. The accuracy of the assessment of adequacy is questioned, as is the cost effectiveness of doing so.     

Variation in the assessment of adequacy in cervical smears

OBJECTIVE: To assess the interobserver reproducibility of the diagnosis of 'adequacy' of cervical smears according to the Bethesda System criteria in cervical smears. STUDY DESIGN: 358 cervical smears were obtained from three Italian cytopathological centres in 1998-99. All centres provided consecutively collected smears. The cervical smears were independently and blindly assessed by four cytologists.The screening was performed using a 10x objective and an additional evaluation of the percentage of cellularity was performed using a 4x objective. RESULTS: The proportion of smears assessed by the four cytologists as 'adequate' ranged from 60% to 70%, the proportion of 'satisfactory for evaluation but limited by' ranged from 27% to 38%, and the proportion of 'inadequate smears' ranged from 2% to 4%. Full agreement in the assessment of smear adequacy was observed in 311 slides and disagreement was observed only in 47. The category 'inadequate smear' was less reliable than the other two; however, the kappa value observed was acceptable. CONCLUSION: The present study shows that it is possible to achieve a high reproducibility in the assessment of smear adequacy, at least among expert cytologists who follow the Bethesda System criteria strictly.     

Examination of cytological smears and clot sections prepared from pleural fluids: a comparative study

Between January 1989 and May 1990, the Department of Cytology of Llandough Hospital examined 784 pleural fluid cytological preparations, 99 of which were also examined as paraffin wax sections of clots that had formed. to assess whether this practice yields worthwhile information, we reviewed the cytology and clot sections of 99 patients with pleural effusions and correlated the results with subsequent histology and review of clinical case notes. the specificities of each method separately and when combined was high: 92% clot section, 85% smear cytology and 85% combined. the sensitivity using clot section alone was 49%, smear cytology alone 46% and in combination, 54%. Analysis showed no significant difference between these sensitivities. When pleural fluid clot formation occurs, we recommend the continued examination of clot sections, since it yields an increase in positive diagnoses, albeit not statistically significant. Entre janvier 1989 et mai 1990, 784 préparations cytologiques de liquides pleuraux ont été examinées dans le département de Cytologie de l'Hôpital Llandough. Parmi ces 784 cas, 99 contenaient un coagulum qui a fait l'objet également de coupes histologiques apres inclusion en paraffine. Afin de déterminer si cette pratique apporte une information intéressante, la cytologie de ces 99 patients et les coupes obtenues á partir du coagulum ont été revues, puis les résultats one été corrélés avec les résultats histologiques et avec I'analyse des données cliniques. Les valeurs de la spécificité de chacune des méthodes et des deux méthodes associées sont élevées: 92% pout les coupes du coagulum, 85% pour la cytologie d'étalement et 85% pour les deux méthodes combinées. Les valeurs pour la sensibilité sont de 49% pour les coupes de coagulum, de 46% pour la cytologie seule et de 54% en combinant les deux methodes. L'analyse ne met pas en évidence de différence significativé de sensibilitk entre les méthodes. Lorsqu'un coagulum s'est formé dans un liquide pleural, nous recornmandons de poursuivre la pratique de l'inclusion en paraffine et de coupe de ce coagulum puisque cette pratique aboutit à une augmentation du taux de diagnostics positifs, même si la différence n'est pas démontrée statistiquement. Das zytologische Labor des Llandough Hospitals untersuchte zwischen Januar 1989 und Mai 1990 784 Pleurapunktate. Von 99 wurden ausserdem paraffinge-schnittone Clotpräparate angefertigt. Um den Wert dieses Verfahrens zu überprüfen wurden diese Ergebnisse mit späteren histologischen Proben und der Patientengeschichte korreliert. Die Spezifitaten betrugen: 92% für Clot, 85% für Ausstriche und 85% für die Kombination. Die Sensitivitäten: 49% für Clot, 46% für Ausstriche und 54% für die Kombination. Die Unterschiede sind statistisch nicht signifikant, trotzdem sollten Gerinnsel bei Vorhandensein histologisch verarbeitet werden.     

BioPEPR: a system for the automatic prescreening of cervical smears.

A feasibility study has indicated that a Prescion Encoding and Pattern Recognition (PEPR) cathode ray tube prescreening system for cervical smears can be both accurate and fast. Smears are prepared using a syringing technique and are stained with a Feulgen-type nuclear stain and a protein counter-stain. The use of film as an intermediate step between the cells and Bio PEPR allows the scanning of fields as large as 8 x 8 mm. The morphological features of the cells are measured as directed by a hierarchical decision strategy. Additional programs detect artifacts, overlaps, and leukocytes. For clean samples, false positive and false negative rates on the cell level have been obtained that will allow acceptable smear level rates (10% false positive, 1% false negative). These rates have been reached without compromising the required speed goals of 120 to 180 smears per hr. The efficiency of the system is dependent on the quality of the smears. Measurements on a set of 192 routinely prepared smears indicate acceptable false negative rates and a false positive rate of about 18%. A reduction of this rate is expected with small improvements in cell preparation and measuring software, leading to the overall system efficiency required for commercial feasibility.     

Evaluation of methods to assess adequacy of potential soil S supply to crops

Eight methods were evaluated for assessment of the likely soil S-supply to a crop and in particular to identify likely deficiencies in this supply. Of the methods, only sulphate production from incubated soil amended both with a S-containing amino acid and elemental S correlated with field response of grass yield to S-fertilizer applications. Tissue S-concentrations in plants grown for a short-term bioassay also correlated with field S-fertilizer response. Neither sulphate extracted by 3 different salt extractions, nor sulphate production from unamended incubated soil, nor soil arylsulphatase activity, correlated with field fertilizer response.     

Adequacy of cervical cytology sampling with the Cervex brush and the Aylesbury spatula: a population based randomised controlled trial.

OBJECTIVE: To compare the adequacy of cervical cytology sampling with two sampling instruments commonly used in primary care-namely, the Aylesbury spatula and the Cervex brush. DESIGN: Pair matched, population based randomised controlled trial. SETTING: 86 general practices and family planning clinics in Greater Manchester. SUBJECTS: 15 882 cervical smears taken from women aged 20-64 years as part of the national cervical screening programme. INTERVENTIONS: Participating centres were allocated to sample with either the Cervex brush or the Aylesbury spatula. MAIN OUTCOME MEASURE: Inadequate smear rate. RESULTS: 5.4% and 5.5% (433/8086 and 426/7796) of smears taken with the Cervex brush and the Aylesbury spatula respectively were reported as inadequate (odds ratio 0.95; 95% confidence interval 0.74 to 1.22). CONCLUSION: The Cervex brush offers no advantage over the Aylesbury spatula in reducing inadequate smear rates in the primary care setting.     

The preparation of additional smears from a cervical scrape: impact on the rate of detection of cervical neoplasia

The preparation of additional smears from a cervical scrape: impact on the rate of detection of cervical neoplasia It has been known for some time that only a proportion of the cells on the smear-taking device is transferred to the slide. This can give rise to errors in reporting although the smear may have been taken correctly. This study was undertaken to identify a quick and simple method of improving the accuracy of the Papanicolaou test. A conventional smear and five additional smears were obtained from 62 women attending a Genito-Urinary Medicine clinic. The cell content of the conventional smears and the additional smears was compared. Dyskaryotic cells were detected both in the conventional smear and in the first and second additional smears from 22 women. Dyskaryotic cells were detected in the first and second additional smears only in five women. Thus, the conventional smear failed to detect biopsy-confirmed cervical abnormality in these women. A cell count of the first additional smear in the five cases where the conventional smear was negative showed that they contained, on average, 310 dyskaryotic cells. The preparation of one additional cervical smear per cervical scrape could significantly increase the accuracy of the cervical smear test by 11% (P=0.025, McNemar's test).     

Immunocytochemical staining of cervical smears for the diagnosis of cervical intraepithelial neoplasia

A total of 233 cervical smears were stained by immunocytochemical methods for epithelial membrane antigen (EMA); the findings were compared with those from Papanicolaou-stained smears from the same women. Squamous epithelial cells from normal cervices did not stain, but cells shed from cervices with cervical intraepithelial neoplasia (CIN) did express the EMA marker. Metaplastic cells from normal and abnormal cervices also frequently stained. The results confirm that this marker detects cervical intraepithelial neoplasia in vitro, but its potential use in an automated screening program may be limited by the staining of the metaplastic cells.     

Cytophotometric study of DNA content of cells in type III cervical smears

Cytophotometric study of suspicious (group III of the Papanicolaou's classification) smears shows the heterogeneity of this group, which includes cases with diploid--tetraploid DNA modes, cases with a wide distribution of DNA values and aneuploid cases. The significance of these findings in relation with the biological properties of cells is briefly discussed.     

Evaluation of proficiency testing as a method of assessing competence to screen cervical smears

Evaluation of proficiency testing as a method of assessing competence to screen cervical smears Regular proficiency testing of pathologists and cytotechnologists who undertake the analysis of cervical smears has been carried out in cytology laboratories in the North Thames (West) Region since 1989. The protocol followed is one that has been adopted nationally. Since the scheme started, laboratory personnel from 17 cytology laboratories in the Region have participated and seven rounds of testing have been completed. Nine hundred and seventy-one tests were carried out and a pass rate of 96.4% was recorded. Two hundred and forty-seven cytologists took the test on at least one occasion and 63 cytologists took part in all seven rounds. Our results indicate that proficiency testing is capable of detecting cytologists who consistently perform below an acceptable standard and require retraining. They also show that even the most competent screeners can miss an abnormal smear. Seven cytologists who had proved their competence to screen on six occasions, missed an abnormal smear on the seventh, despite the fact that they were screening under test conditions when their vigilance should have been at its peak. Our findings indicate that false-negative reporting will inevitably occur during manual screening, and emphasize the need for further research into the causes and prevention of screening error. Evaluation des tests d'aptitude comme méthode d'appréciation de la compétence à lire les frottis cervico-utérins de dépistage Le passage régulier de tests d'aptitude pour les pathologistes et les cytotechniciens qui prennent en charge l'analyse de frottis cervico-utérins est utilisé dans les laboratoires de cytologie de la région North Thames (West) depuis 1989. Le protocole choisi est l'un de ceux qui ont été adoptés au niveau national. Depuis le début de ce programme, 7 sessions de tests ont été organisées et le personnel de 17 laboratoires de cytologie de la région a participé. Neuf cent soixante et onze tests ont été pratiqués et le taux de participation enregistré est de 96,4%. Deux cent quarante sept cytologistes ont fait le test au moins une fois et 63 cytologistes ont passé les 7 sessions de tests. Nos résultats indiquent que les tests d'apitude sont capables d'identifier les cytologistes qui ont besoin d'une formation car leur résultats aux tests sont régulièrement en dessous des standards acceptables. Ils montrent également que même les “screeners” les plus compétents peuvent passer à côté d'un frottis anormal. Sept cytologistes ayant montré leur compétence pour la lecture des frottis de dépistage sur 6 tests n'ont pas été capable de détecter un frottis anormal sur le septième test, bien que cette lecture ait été faite dans des conditions de test où leur vigilance aurait dû être à son maximum. Ces résultats indiquent qu'il est impossible d‘éviter les faux négatifs au cours du “screening manuel” et confirment la n?essité de poursuivre les recherches sur les causes des erreurs de lecture et sur leur prévention. Die Ergebnisse der Laistungstests als Grundlage für die Fähigkeit gynäkologische Abstriche auszuwerten Regelmässige Leistungstests von Zytopathologen und Zytotechnikerinnen beim Auswerten gynäkologischer Abstriche wurden seit 1989 in den Labors der Nord-Themse Region durchgeführt. Das Testprotokoll entspricht dem landesweit angewandten. Inzwischen nahmen 17 Labors an insgesamt 7 Testrunden teil. Die Gesamtzahl der Tests beträgt 971 wobei 96,4% der Teilnehmer die Tests bestanden. 247 Teilnehmer nahmen an zumindest einem Test, 63 an allen sieben teil. Die Auswertungen ergaben, dass auf diese Weise Zytologen mit unterdurch schnittlicher Leistung identifiziert und einem Zusatztraining zugeführt werden können. Sie zeigen aber auch, dass selbst die Erfahrendsten gelegentlich positive Befunde übersehen. Sieben Teilnehmer begingen diesen Fehler nach sechs fehlerfreien Durchgängen beim siebten Test trotz der bekannten Testsituation. Dies bedeutet, dass Fehler bei nichtautomatischer Auswertung unvermeidbar sind. Die Ursachenforschung muss weitergeführt werden.     

Rapid rescreening of cervical smears as a quality control method

Rapid rescreening of cervical smears as a quality control method The use of a rapid rescreening method as part of an internal quality control programme is reported. During a 12-month period 33 976 smears were reviewed (90.9% of total workload). Two-hundred and nineteen reports were altered, with 23 dyskaryotic smears identified, a false-negative rate of 0.07%, a false-negative dyskaryotic rate of 1.7%. Smears reported as dyskaryotic were also subjected to the rapid screening method (with 86.8% correctly identified) as well as using the method to assess smears before the usual primary screen (with 67.2% of dyskaryotic smears correctly identified). Rapid rescreening as a quality control method is effective, and although it has limitations, should replace 10% proportional rescreening as the preferred daily quality control method of choice. La relecture rapide des frottis cervico-utérins comme méthode de contrôle de qualité Ce travail décrit l'utilisation de la méthode de relecture rapide dans le cadre d'un programme de contrôle de qualité interne. Pendant une période de 12 mois, 33 976 frottis ont été revus (90,9% du recrutement). Deux cent dix neuf comptes-rendus ont été modifiés dont 23 concernant des frottis avec dyscaryoses, ce qui donne un taux de faux négatifs de 0,07% et un taux de faux négatifs pour les dyscaryoses de 1,7%. La méthode rapide a été appliquée à la relecture des frottis initialement classés comme dyscaryotiques (86,8% ont été correctement identifiés) ainsi qu'a la lecture de frottis avant le screening primaire (avec 67,2% de frottis dyscaryotiques correctement identifiés). La méthode de relecture rapide utilisée comme méthode de contrôle de qualité est efficace et, malgré ses limitations, elle devrait remplacer la relecture de 10% comme méthode de contrôle de qualité de routine. Rasches Nachscreenen als Methode der Qualitätskontrolle Während 12 Monaten wurden 33.976 Abstriche durch rasches Nachscreenen überprüft (90,9% aller Abstriche). 219 Befunde wurden abgeädert darunter 23 neue Dyskariosen, Dies entspricht einer Rate falsch negativer von 0,07% und falsch negativer Dyskariosen von 1,7%. Sämtliche Dyskariosen wurden ebenfalls überprüft mit einer Ausbeute von 86,8%, während die Methode als Vorlauf vor dem normalen Screening 67,2% erfasste. Trotz ihrer Einschränkungen ist die Methode wirkungsvoll und sollte die übliche Überprüfung von 10% der negativen Abstriche ersetzen.