Pleural Fluid Lactic Acid as a Probable Diagnostic Aid

To the Editor.— In MEDICAL NEWS William Check (241:781, 1979) reviewed the accuracy of determination of the level of lactic acid in CSF and synovial fluid for the differential diagnosis of bacterial infection. Studies should be conducted to measure the lactic acid concentration in pericardial, pleural, and peritoneal fluids to help the physician in diagnosis and management (241:781, 1979). The lactic acid concentration in pleural fluid that may probably aid in the definite diagnosis of empyema is reported. A total of 41 patients younger than 12 years of age were studied and divided into two groups, empyema and nonempyema cases. Empyema was diagnosed on the basis of purulent pleural fluid and presence of bacteria on stain and culture; these cases required intercostal drainage for resolution. The nonempyema cases were those with pleural effusion from other causes and did not require intercostal drainage for resolution. None of the cases received any