Fibronectin concentration in ascites differentiates between malignant and nonmalignant ascites.

Differentiation between malignant and nonmalignant ascites by means of laboratory parameters has so far not been completely achieved. One hundred and four patients with ascites (34 malignant, 51 cirrhotic, and 19 other) were studied for fibronectin concentration in ascites. The first 47 patients (13 malignant and 34 cirrhotic) were used to determine mean values and standard deviation (178 +/- 96 vs. 8.3 +/- 15.3 micrograms/ml) and to define a cutoff concentration between both groups (75 micrograms/ml). Several other parameters were analyzed simultaneously in these patients (total protein: 3.93 +/- 1.46 vs. 1.50 +/- 1.02 g/dl; white cell count: 2022 +/- 1153 vs. 569 +/- 405/mm3; lactic acid: 3.86 +/- 2.57 vs. 1.83 +/- 0.72 mmol/L; lactic acid dehydrogenase: 357 +/- 329 vs. 61 +/- 35 U/L; serum/ascites ratio of lactic acid dehydrogenase: 1.11 +/- 1.13 vs. 4.06 +/- 2.00; pH: 7.275 +/- 0.229 vs. 7.513 +/- 0.042). Their accuracy (mean of sensitivity and specificity) was always less than 87% due to a considerable overlap between both groups. Five patients with other causes of ascites could not be classified at all. Application of fibronectin determination on the subsequent 57 patients (21 malignant, 17 cirrhotic, and 19 other) revealed a sensitivity, specificity, and negative and positive accuracy for malignant ascites of 100%. Calculation of these parameters for all 104 patients gave identical values. The inclusion of 3 patients without final diagnosis in the group of nonmalignant ascites reduced specificity to 97.1 and positive accuracy to 94.4%. However, these values were superior to all other methods used so far. Fibronectin determination in ascites in combination with other parameters suitable for exclusion of infectious or pancreatic origin of ascites may prove useful in the differential diagnosis of ascites.