A further application of the nitroblue tetrazolium test.

The nitroblue tetrazolium (N.B.T.) test was performed on patients in whom a differential diagnosis of pulmonary thromboembolism or lobar pneumonia existed. The mean N.B.T. score in healthy subjects was 6.4% (range 1%-15%). Patients with uncomplicated pulmonary thromboembolism showed a mean N.B.T. value of 7.5% (range 3%-12%). In patients with lobar pneumonia the mean N.B.T. score was 42.4% (range 21%-85%). These results suggest that the N.B.T. test is of value in the differential diagnosis of pulmonary thromboembolism and lobar pneumonia.