The diagnostic value of cytochemical staining for non-specific esterase in the search for cancer cells in effusions.

143 consecutive effusion samples were stained for non-specific esterase (NSE) in order to test the diagnostic value of the staining method with reference to the diagnosis of carcinosis in pleural and peritoneal cavities. On comparing the results obtained by cytomorphological evaluation and NSE staining the former was proved to have a signficnat higher diagnostic specificity. The diagnostic sensitivity of the two methods showed no difference. The low diagnostic specificity of the NSE staining was due to occasionally intense staining of macrophages and mesothelial cells in connection with reactive states of the mesothelium. The NSE staining is not recommendable as a diagnostic supplement to the cytomorphological evaluation.