Diagnostic value of ferritin measurements in patients with pleural effusions.

The diagnostic value of ferritin measurements has been evaluated in 59 patients with pleural effusions (PE). The Mean(+/- standard error [SE]) PE-ferritin level was 1913 +/- 720 ng/ml in 10 patients with nonmalignant nontuberculous (nonTB) exudates (Group I), 594 +/- 110 ng/ml in 14 patients with TB effusions (Group II), 1286 +/- 194 ng/ml in 28 patients with malignant exudates (Group III), and 280 +/- 60 ng/ml in 7 patients with transudates (Group IV). Significant difference was found between Group II and Group III (p less than 0.05). The mean (+/- SE) ratio of PE/serum (PE/S) ferritin in Groups I, II, III, and IV was 3.5 +/- 1.1, 10.5 +/- 5.1, 4.9 +/- 1.0, and 2.0 +/- 0.7, respectively, and it showed no significant difference among Groups I, II, and III. There were good correlations between PE-ferritin and PE-LDH or S-ferritin, but no correlation between PE-ferritin and PE-protein. PE-ferritin revealed a considerable overlap among the exudative groups, and was of no value in the differentiation between malignant and nonmalignant (Group I + II) exudates. In the discrimination between exudates and transudates, the diagnostic accuracy (86%) of PE-ferritin was inferior to those (all 98%) of PE-protein, PE-LDH, PE/S protein ratio, and PE/S LDH ratio. Using PE-ferritin greater than or equal to 500 ng/ml in distinguishing malignant exudates from TB effusions, the sensitivity was 79%, specificity 57% and accuracy 71%.(ABSTRACT TRUNCATED AT 250 WORDS)