Orosomucoid contents of pleural and peritoneal effusion of various etiologies.

Orosomucoid and the contents of seven other proteins were determined by radial immunodiffusion in sera and in pleural or peritoneal fluids of 66 patients. No significant difference between concentration of individual proteins in effusions of neoplastic origin and those of nonneoplastic inflammatory origin was found. In noninflammatory fluids, the protein concentrations were lower, but their distribution was similar to distributions in the other fluids tested. These findings support the view that the protein content of effusions reflects changes in vascular permeability.