The nitroblue tetrazolium test in patients with advanced neoplastic diseases

The nitroblue tetrazolium test (NBT) was evaluated in 111 patients with cancer. Patients were placed into control and 'presumed infected' groups. The mean NBT score for the control group, 6.3, was significantly greater than the mean for a group of normal volunteers, 3.1, but the mean score for the 'presumed infected' group, 15.6, was significantly higher. Less than 10% of the patients with bacterial infection had scores below 10, while 15% of the control patients had unexplained high scores. A method for concentrating leukocytes is described which makes the NBT test feasible in patients with granulocytopenia. Morphological changes in granulocytes used as indicators of infection are unreliable markers in cancer patients, in whom such changes occur frequently in the absence of infection. The authors have found that the NBT test is more useful as an indicator of infection in patients with cancer.