Ascitic fluid analysis for the differentiation of malignancy related and nonmalignant ascites

The authors tried to differentiate malignancy-related from
nonmalignant ascites with a sequence of sensitive followed by
specific ascitic-fluid parameters. There were four results of this
study. First, of nine parameters investigated in a first series of
48 patients, 28 with nonmalignant and 20 with malignancy-related
ascites, ascitic-fluid cholesterol and fibronectin yielded the best
negative predictive value of 92% each. Carcinoembryonic antigen
(CEA) and cytologic examination both showed a positive predictive
value of 100%. Second, combining cytologic examination
(sensitivity, 70%) and CEA determination (sensitivity, 45%)
increased the sensitivity to 80%. Third, cytologic findings were
negative in all ascitic-fluid samples with a cholesterol
concentration below the cutoff value of 45 mg/100 ml. Fourth, based
on the results of the first series of 48 patients, the diagnostic
sequence with cholesterol as a sensitive parameter, followed by the
combination of cytologic examination and CEA determination as
specific parameters, was tested in a second series of 71 patients,
37 with nonmalignant and 34 with malignancy-related ascites. Again
cytologic examination was negative in all samples with cholesterol
levels below 45 mg/100 ml. In the total of 119 patients, this
diagnostic sequence did not identify 9% of patients with
malignancy-related ascites, and 82% of samples classified as
malignancy related by cholesterol levels above 45 mg/100 ml were
confirmed by positive cytologic examination and/or CEA level above
2.5 ng/ml. Thus, a diagnostic sequence with ascitic-fluid
cholesterol determination, followed by cytologic examination and
CEA determination, in samples with cholesterol levels above 45
mg/100 ml should permit a cost-efficient routine differentiation of
malignancy-related from nonmalignant ascites.