Interpretation

A peritoneal fluid carcinoembryonic antigen (CEA) concentration greater than 6.0 ng/mL is suspicious, but not diagnostic, of malignancy-related ascites. This clinical decision limit cutoff yielded 48% sensitivity and 99% specificity in a study of 137 patients presenting with ascites. CEA concentrations were significantly higher in ascites caused by malignancies known to be associated with elevated serum CEA levels, including lung, breast, ovarian, gastrointestinal, and colorectal cancers. However, ascites caused by other malignancies, such as lymphoma, mesothelioma, leukemia, and melanoma and hepatocellular carcinoma, routinely had CEA concentrations less than 6.0 ng/mL. Therefore, negative results should be interpreted with caution, especially in patients who have, or are suspected of having, a malignancy not associated with elevated CEA levels in serum.