© 2000 by Oxford University Press
Brief report. Lysozyme levels for the diagnosis of tuberculous effusions in children
Departments of A Pediatrics, B Biochemistry, and C Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi-221 005, India Corresponding author address: 12 GF, Kabir Colony, P.O. B.H.U., Varanasi-221 005, India Tel: 0542 317654 Fax: 0542 316068
Lysozyme level was measured in the fluid and serum of 42 tuberculous (25 pleural, 11 ascites and 6 pericardial) and 29 non-tuberculous (5 malignant, 9 empyema thoracis, 10 transudative ascites and 5 pyopericardium) effusions. The mean fluid lysozyme level was significantly raised in tuberculous pleural, ascites, and pericardial effusions in comparison to malignant pleural (p < 0.001), transudative ascites (p < 0.001), and pyopericardium (p < 0.02) cases, respectively. The mean fluid/serum lysozyme ratio did not differ significantly between tuberculous and their corresponding non-tuberculous effusions. The confirmed tuberculous pleural effusion patients had significantly higher mean fluid lysozyme level and fluid/serum lysozyme ratio when compared with clinical cases (p < 0.05). The cut-off fluid lysozyme level of 
50/Ul-1 and fluid/serum lysozyme ratio of 1.1 were considered for the diagnosis of tuberculous effusions; the sensitivity and specificity of fluid lysozyme and fluid/serum lysozyme ratios were 100, 100 per cent, and 97.6, 33.3 per cent, respectively, on excluding the patients with purulent effusions. A significant correlation was observed between the fluid and serum lysozyme levels in tuberculous effusions (r=0.39, p<0.01). Thus, fluid lysozyme was found to be a better and reliable test than fluid/serum lysozyme ratio for the diagnosis of tuberculous effusions in children.