Nitroblue tetrazolium test is a blood test that measures the ability of the immune system to convert the colorless nitroblue tetrazolium (NBT) to a deep blue. This test is performed as a screen for chronic granulomatous disease (CGD). If an individual has CGD, the white cells in their blood will not turn blue when exposed to the NBT.
Update Date 1/21/2013
Updated by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, Bethanne Black, Stephanie Slon, and Nissi Wang.