Diagnostic significance of pH, lactic acid dehydrogenase, lactate and glucose in pleural fluid.

The pH, lactic acid dehydrogenase, lactate and glucose of pleural fluid simultaneous with serum lactic acid dehydrogenase, blood lactate and glucose were determined in 105 pediatric patients. The patients were classified into groups according to the diagnosis. The pleural fluid of empyema cases was found to have the lowest pH with a mean value of 6.83 (p less than 0.0075). The malignant pleural fluid has a relatively low pH with a mean value of 7.32. The lactic acid dehydrogenase in pleural fluid of empyema cases has the highest mean of 1,470.68 (p less than 0.05). The lactic acid dehydrogenase was found increased in malignancy, tuberculosis and parapneumonic effusion cases. Lactate level was found extremely high in empyema cases with a mean value of 13.68. It was also found extremely high in malignancy, tuberculosis and parapneumonic effusion cases. The glucose level was markedly decreased in empyema cases. There exists correlation of pleural fluid lactate to pH, lactic acid dehydrogenase and glucose, as well as that of pH to lactic acid dehydrogenase.