LACTATE DEHYDROGENASE ISOENZYMES PATTERN IN DIFFERENTIAL DIAGNOSIS OF PLEURAL EFFUSIONS

Abstract

Objectives: Total lactate dehydrogenase (LD) in the pleural fluid (PF) is of little value in the discrimination of various types of exudative effusions such as malignant from non-malignant effusions.The aim of this study is to assess the diagnostic value of LD isoenzymes activity in serum & pleural fluid in the differentiation between various exudative pleural effusions. Methods: Sixty-Six patients with pleural effusions were included in the study. Activity of total LD & isoenzyme were measured in pleural fluid & serum. Isoenzymes were separated by agarose gel electrophoresis & the quantity of each isoenzyme was measured by spectrophotometer.Results: Exudative (inflammatory, neoplastic) effusions had a relatively high LD levels compared to transudates. LD isoenzymes pattern was significantly different between transudates & exudates.PF LD isoenzymes pattern differs from that in serum. Our results showed that mainly the pattern of LD3 in pleural fluid & serum was helpful in discriminating inflammatory exudates from neoplastic exudates.Conclusion: The LD isoenzyme pattern differed between pleural effusions of transudative and exudative origin. Moreover including the LD isoenzyne activities in the biochemical work up of pleural effusions reveal an additional discriminatory value in the separation between various exudative effusions, especially between inflammatory exudate & neoplastic exudates.Keywords:Pleural effusion,lactate ehydrogenase isoenzymes