Quantitative sputum analysis: Neuraminidase and tuberculosis

Objectives Clinically sensitive screening tests for pulmonary tuberculosis. Methods Quantitation of sputum lysosomal enzymes derived from mycobacterium-infected macrophage. Neuraminidase in culture-positive sputa exemplifies such systems. Results Correlation coefficient between sputum neuraminidase values (n = 18), obtained by fixed-volume samplers and variable volume micropipets, was 0.995. Mean sputum neuraminidase values among tuberculous (137) and non-tuberculous (117) patients were 15.08 and 0.90 mU per mL. Medians were 8.45 and 0.20 mU per mL. Non-parametric analysis concludes a significant difference between the groups at P < 0.001. Sputum neuraminidase levels above 1.0 mU per mL characterized 126 of 137 tuberculosis patients (92.0%). Conclusions (1) Calibrated sputum fluid samplers facilitate quantitation of sputum enzymes. (2) Sputum neuraminidase levels over 1.0 mU per mL associate with Mycobacterium tuberculosis in 92% of cases. (3) Sputum neuraminidase measurements offer a screening procedure with which to identify samples for more specific, but less sensitive tests.