Combined Carcinoembryonic Antigen and Cytopathologic Examination in Ascites

To investigate use of the combined carcinoembryonic antigen (CEA) test and cytopathologic examination to improve the diagnosis of neoplastic vs. nonneoplastic ascites. The tests were performed prospectively on 130 patients with ascites whose effusions were submitted for cytologic examination. Sixty-seven patients had epithelial tumors, and the cytologic examination was positive in 39 (58.2%). The CEA level was > or = 11.0 ng/mL in 36 patients (53.73%). CEA was helpful in the diagnosis in 18 cases, increasing to 57 (85.07%) the number of positive diagnoses. Eight samples of nonepithelial tumors had low levels of CEA. In 55 patients with nonneoplasic ascites the cytopathologic examination was negative, but the CEA assay was > 11.0 ng/mL in 3 patients. The cytopathologic examination should be performed in all cases, and the CEA assay should be done in suspected cases of epithelial neoplasia in which the cytologic examination was negative, there was uncertainty about the histologic type of neoplasia, or a diagnosis of nonepithelial neoplasia was made. When ascitic leukocytosis or hepatic failure is present, one should be cautious in interpreting the CEA assay because false positivity can occur.