Diagnostic accuracy of toluidine blue-stained wet films in effusion cytology

OBJECTIVE: To evaluate the usefulness of toluidine blue-stained wet films in the preliminary cytologic evaluation of serous effusions by means of specificity, sensitivity, and positive and negative predictive value. STUDY DESIGN: One hundred seventy-six samples consisting of 122 pleural and pericardial effusions and 54 peritoneal effusions from 160 patients were included in the study. A toluidine blue-stained wet film of each sample was evaluated, and diagnoses were compared with the diagnoses by conventional smears and cell blocks on the same sample. RESULTS: The sensitivity of wet films was 69%, 68% in pleural and pericardial effusions and peritoneal effusions, respectively, and the specificity of wet films was 93%, 92% in pleural and pericardial effusions and peritoneal effusions, respectively. Positive predictive values of smears alone were 78% and 75%; negative predictive values of smears alone were 96% and 95% in pleural and pericardial effusions and peritoneal effusions, respectively. CONCLUSION: Preliminary cytologic evaluation of serous effusions with toluidine blue-stained wet films is simple and economical. It provides the opportunity to plan additional procedures for the samples.