Diagnostic value of biochemical analysis of pleural effusions. Carcinoembryonic antigen and beta 2 microglobulin.

Pleural effusions from 105 patients with malignant and nonmalignant diseases were examined for tumor cells, content of CEA, beta2 microglobulin, ceruloplasmin, alpha2 macroglobulin, orosomucoid, lysozyme, and hexosaminidase. Only CEA and beta2 microglobulin determinations were of diagnostic value. CEA concentrations greater than 11 ng/ml were found only in malignant effusions. Beta 2 microglobulin values were increased in pleural effusions due to lymphoma or immune diseases. Measurement of CEA and beta2 microglobulin in addition to the cytologic examination could increase the diagnostic significance of the analysis of pleural effusions.