Abstract
A new modification of the nitroblue‐tetrazolium (NBT) test for the detection of chronic granulomatous disease is described. Phagocytosis is initiated by particles of killed Candida albicans which are easily seen and counted. The three genetic groups are identified unequivocally and without any overlapping, as demonstrated in 140 tests of 125 normal controls, 10 tests of 7 hemizygous mothers and 17 tests of 11 affected patients. The accurate working procedures are fully described.