NBT Reduction Test
Nitroblue tetrazolium reduction test
(specialist request only)
When Chronic granulomatous disease is suspected (CGD): history
of recurrent or severe staphylococcal infections/abscesses or
infections with other gram positive bacteria, invasive fungal
infections (when other causes of immunodeficiency have been
excluded), multiple granulomatous lesions.
Assay measures the phagocytic activity of polymorphonuclear
leucocytes by the amount of colour change of NBT.
Request via ICE.
Assay performed as required.
It is essential to provide relevant clinical information.
It is essential to telephone laboratory to arrange the test.
No special preparation is required but a travel control is
Samples are sent to the referral
laboratory immediately on receipt and tested the same
Samples should be transported to the laboratory immediately.
Aliquot and store at 4-8°C prior to testing and at -20°C or
below for up to 1 month after receipt.
Causes for Rejection
Unlabelled/inadequately labelled sample
Inadequately completed request form
Delay in sample reaching laboratory.
Assay is reported as a percentage of polymorphic leucocytes that
contain blue dye particles. Patients with CGD will have very low or
zero values, female carriers will have an intermediate level of