Ferritin Assay in Malignant Pleural Effusion

In order to assess the usefulness of ferritin as a tumor marker, the authors measured and analyzed pleural fluid and serum ferritin concentrations by double antibody radioimmunoassay method in 20 patients with malignant pleural effusion, and in 39 patients with benign pleural effusion. Serum ferritin levels were also measured in a control group of 20 healthy people. 1) Pleural fluid ferritin levels in the malignant pleural effusion group were significantly higher (p<0.001) than those of the benign pleural effusion group. 2) As one of the criteria in differentiating between malignant and benign pleural effusion, the differentiating pleural fluid ferritin level was set at 2,000 ng/ml, a specificity up to 75.0% and sensitivity of 89.7% could be obtained. 3) Serum ferritin levels in the malignant pleural effusion group were significantly higher (p<0.001) than those in the control group. 4) There was no statistically significant correlation between pleural fluid and serum ferritin levels in the malignant pleural effusion group. From the above results, it can be concluded that it is possible to use pleural fluid ferritin levels as a tumor marker.