Nitrobule tetrazolium test in the diagnosis of pleural effusions

This study evaluated the diagnostic utility of the nitroblue tetrazolium test on pleural fluid. Pleural fluids from 62 patients, including nine with congestive heart failure, 27 with malignant neoplasms, nine with tuberculosis, 14 with pneumonia, and three with collagen vascular disease, were studied. Results of nitrobule tetrazolium were tabulated for each patient for three different cellular types (polymorphonuclear leukocytes, small lymphocytes, and mononuclear cells other than small lymphocytes). The three patients with collagen vascular disease had very high scores on the nitrogen tetrazolium test for all three cellular types. Their average scores were higher than were those of 57 of the other 59 patients. The nitroblue tetrazolium test on pleural fluid was not useful in separating patients with congestive heart failure, pneumonia, malignant neoplasms, or tuberculosis. The results on the nitroblue tetrazolium test did not help to identify those patients with pneumonia who eventually required tube thoracostomy. From this study, we conclude that the nitroblue tetrazolium test on pleural fluid is of limited use diagnostically but may help to identify those individuals with collagen vascular disease involving the pleura.