Value of carcinoembryonic antigen (CEA) and cholesterol assays of ascitic fluid in cases of inconclusive cytology.

AIM To determine whether assays of carcinoembryonic antigen (CEA) and cholesterol in ascites add diagnostic value to cytology. METHODS The additional diagnostic efficacy of the biochemical assays was studied in the ascitic fluid from 130 patients, of whom 57 had peritoneal carcinomatosis. All diagnoses were verified by subsequent necropsy and/or histology. RESULTS CEA concentrations over 5 ng/ml indicated carcinomas, occasionally without peritoneal involvement of the tumour. However, increased values were significantly more common in cancer with peritoneal involvement (p < 0.01), giving a sensitivity of 51% and specificity of 97% for carcinomatosis. A cholesterol value exceeding 1.21 mmol/litre was found in 93% of cancers with peritoneal involvement, but it was not entirely specific (96%) for carcinomatosis. Simultaneous increases in CEA and cholesterol concentrations were specific for carcinomatosis and this combination increased the sensitivity for diagnosing carcinomatosis from 77% with cytology alone to 88%. The correct diagnosis could thus be made in five of 12 cases with inconclusive cytology. CONCLUSIONS The measurements of both CEA and cholesterol concentrations in ascites give additional specific information about peritoneal carcinomatosis and can therefore be a useful adjunct to cytology-in particular, in inconclusive cases.