DIAGNOSTIC-VALUE OF FERRITIN, HAPTOGLOBIN, ALPHA(1)-ANTITRYPSIN, LACTATE-DEHYDROGENASE AND COMPLEMENT FACTORS C3 AND C4 IN PLEURAL EFFUSIONDIFFERENTIATION

Searching to define diagnostic criteria for malignant and non-malignan t pleural effusions, the differential diagnostic value of ferritin (FR T), haptoglobin (Hp), alpha(1)-antitrypsin (alpha(1)-AT), lactate dehy drogenase (LDH) and complement factors C3 and C4 were investigated pro spectively in 100 consecutive patients with pleural effusions of vario us aetiologies. Pleural effusion FRT, C3 and C4 concentrations were fo und to be useful in differentiating exudates from transudates, so that transudates practically could be excluded in pleural effusion: serum FRT ratio lower than 0.5 and/or in pleural effusion values for C3 and C4 higher than 300 mg dl(-1) and 70 mg dl(-1), respectively. A pleural effusion: serum C3 ratio greater than 2 is seen only in malignant eff usions. No discriminative pleural: serum ratio could be found in FRT a nd C4 values capable of differentiating malignant from non-malignant e ffusions. Pleural effusion alpha(1)-AT and LDH values were elevated in exudates, as compared with transudates, and had an excellent sensitiv ity and predictive value, but low specificity, in differentiating mali gnant from non-malignant effusions. Finally, the sensitivity, specific ity and positive predictive value of pleural effusion Hp concentration s were lower than those of FRT and complement factors C3 and C4, respe ctively.