Tuberc Respir Dis.  1985 Dec;32(4):259-265. 10.4046/trd.1985.32.4.259.

Diagnostic Value of LDH and its Isoenzyme in Pleural Effusion

• KMID: 2528723
• DOI: http://doi.org/10.4046/trd.1985.32.4.259

Abstract

Pleural fluid LDH measurement and its isoenzyme electrophoresis were performed in 44 exudative pleural effusion patients. 19 cases were malignant effusion, 17 cases tuberculosis and 8 cases miscellaneous causes, respectively. Pleural fluid LDH level and pleural fluid LDH/serum LDH ratio were of no value in differential diagnosis of pleural effusion. High level of LDH₄ and LDH₅ was observed in both benign and malignant pleural fluid and was thought as a common phenomenon of exudates. In about 30% of malignant effusion, LDH isoenzyme pattern showed typical transudate or serum like pattern(sum of LDH₁ and LDH₂ above 55%, sum of LDH₄ and LDH₅ below 15%). No other benign cases except acute pulmonary embolism showed such pattern. Thus, transudate or serum like pattern of LDH isoenzyme in pleural exudate strongly suggests malignancy when the diagnosis is in question The author also suggests a hypothesis that in malignant pleural effusion, LDH isoenzyme pattern in pleural exudate might change with time interval and the change might be related to the pathogenesis of malignant effusion. To confirm it, an animal study or sequential analysis of pleural fluid LDH isoenzyme in the same patient should be performed.