The granulocyte nitroblue tetrazolium reductase test.

The nitroblue tétrazolium (N B T ) test is most useful for the diagnosis of chronic granulomatous disease and a few other rare metabolic abnormalities of neutrophils. It may be helpful in suggesting the presence of infection when values of both percentage of N BT positive neutrophils and total number of N BT positive neutrophils are markedly increased. Each patient must be inter­ preted with cautious attention to the primary disease and other clinical and laboratory findings. Diseases associated with necrosis, such as malignancies and myocardial infarction, will often cause elevation of neutrophil count and increased conversion of NBT. The NBT test may be useful in differentiating acute monocytic leukemia from acute myeloblastic leukemia.