Accuracy and reproducibility of estimating the adequacy of the squamous component of cervicovaginal smears.

In the Bethesda System for reporting cervicovaginal cytology results, 1 criterion for smear adequacy is an adequate squamous component. The accuracy of a cytologist's estimate that 10% of the slide is covered by squamous cells, the adequacy threshold, has not been determined. The percentage of the surface of a glass slide covered by squamous cells was independently estimated by 4 cytologists on 2 occasions by microscopic examination of 83 buccal smears prepared to display estimated coverage of 1% to 20% of the slide surface. The accuracy of visual estimates was compared with measurements by the TracCell System. Each observer made a third set of estimates after receiving 5 slides with known coverage. Median coverage by visual estimation ranged from 4% to 25%, but as measured by the TracCell system was 2%. Median estimated coverage was significantly different for 2 of 4 observers between first and second viewings and between all but 1 pair of observers. For all observers, it was significantly higher than the true coverage. A visual estimate of 10% coverage corresponded to a true median coverage of 3%. When provided with a physical standard, the median estimated coverage by 3 of 4 observers was not statistically different from the true coverage, and interobserver kappa values improved. Unaided visual estimation of the adequacy of squamous cell coverage is neither reproducible nor accurate. What most cytologists consider "adequate" coverage represents only 3% coverage. The availability of a physical standard dramatically increases reproducibility and accuracy.

Receiver operating characteristic curves for analysis of the results of cervicovaginal smears. A useful quality improvement tool.

OBJECTIVES: To assess the value of receiver operating characteristic curves (ROCs) as a tool for improvement in the evaluation of cervicovaginal smear results. DESIGN: We reviewed the results of cervicovaginal smear interpretation for 1 year by 10 different cytopathologists working in the same laboratory (total number of cases, 45,356) and compared them with results of histologic evaluation of corresponding biopsies (n = 2090, 4.6%), the latter taken to be the gold standard. Receiver operating characteristic curves were generated for the laboratory as a whole and for individual cytopathologists. RESULTS: Analysis of these receiver operating characteristic curves was surprisingly informative. They showed that cytopathologists with different diagnostic thresholds could be distinguished from each other. A difference in diagnostic threshold could be distinguished from a difference in diagnostic accuracy. CONCLUSIONS: We conclude that while receiver operating characteristic curves for cervicovaginal smear interpretation have limitations, the results can be used for quality improvement.

The role of cytologic evaluation of pleural fluid in the diagnosis of malignant mesothelioma.

STUDY OBJECTIVE: Treatment of malignant mesothelioma (MM) at an early stage results in increased survival. Cytologic examination of pleural effusions is one of the first diagnostic techniques attempted in these patients. The objective of this study was to define the role of cytologic examination of pleural fluid in facilitating early diagnosis. DESIGN: The medical records and cytologic slides of patients with pleural MM were reviewed. SETTING: Medical records were reviewed from two institutions: a large general hospital and a cancer hospital. PATIENTS: Twenty-nine patients ranging in age from 32 to 81 years (mean, 59 years) met the study criteria. INTERVENTIONS: All patients had at least one cytologic pleural fluid examination. MEASUREMENTS AND RESULTS: The median time from initial symptoms to the diagnosis of MM was 8 weeks for all patients. For patients with a positive or suspicious cytologic result, the median was 4 weeks, and in those with a negative cytologic result, it was 12 weeks. The overall sensitivity of cytologic examination for the diagnosis of MM was 32%. Cytogenetic analysis of pleural fluid had a sensitivity of 56%, and was positive in 1 case in which results of cytologic examination were negative. Patients in whom the time from presentation to diagnosis was greater than 1 year all had negative cytologic results followed by long periods without further workup, despite a history of exposure to asbestos. CONCLUSIONS: A positive or suspicious cytologic result was associated with a decreased median time to diagnosis. Unfortunately, the sensitivity of cytologic examination for a diagnosis of MM was only 32%. Until better diagnostic techniques are developed, we recommend immediate pleural biopsy in patients in whom MM is suspected and cytologic evaluation of pleural fluid gives negative results.