Pleural adenosine deaminase determination combined with differential cell counts for early discrimination of exudative pleural effusion in children

Abstract

Introduction: Increased pleural fluid adenosine deaminase (ADA) activity is feasible association with tuberculous (TB) pleurisy in adults. However, increased activity also occurred in a number of other diseases, and it may not be clarified in children with exudative pleural effusion. Objective: To determine whether the combined use of ADA activity and classic markers (pH, glucose, proteins, LDH, leukocytes and differential count) would provide a more efficient means for the early discrimination of complicated parapneumonic pleural effusion from TB pleurisy than the use of ADA levels alone. Methods: Biochemistry, cytology, and microbiology studies were performed on the pleural fluids from twenty-four children with pleural effusion, who were diagnosed at Hanyang University Hospital from May 1998 through December 2003. ADA and differential cell counts were determined on all exudative effusions. Results: ADA activity in TB effusion was apparently higher (> 100 IU/L) than those in parapneumonic effusion group including mycoplasma infection, although some of them were overlapped. When a neutrophil/lymphocyte ratio of 1.0 or greater was additionally observed, complicated parapneumonic effusion might be highly suggested. The ratios were well correlated with the level of ADA (r = -.224; p < .05). Conclusion: Determination of the levels of ADA combined with neutrophil/ lymphocyte ratios in pleural fluid offers high performance in its early discriminating capacity to identify complicated parapneumonic pleural effusion from TB pleurisy in children. Keywords: pleural effusion; paediatrics