Examination of cytological smears and cell blocks of pleural fluid: Complementary diagnostic value for malignant effusions

Abstract

ObjectivesTo evaluate the independent usefulness of pleural fluid smear and cell block (CB) preparations for the diagnosis of malignant effusions. Patients and methodsA total of 632 cytological smears and 554 CBs from 414 consecutive patients with malignant effusions were retrospectively evaluated. ResultsThe diagnostic yield of a first specimen was 44% regardless of whether a smear or CB cytologic examination was performed. The use of subsequent separated specimens increased the identification of malignancy to 56%. Overall, 11% of samples found to be negative by cytologic smears showed malignant cells on CBs, whereas 15% of negative CBs were reported as positive on smear slides. Pleural fluid specimens with low red and/or white blood cell counts more frequently resulted in the generation of suboptimal CB preparations. ConclusionsIf CBs and smears are prepared and examined, the percentage of positive diagnoses will be greater than if only one method is used.