Nitroblue Tetrazolium Test
Pronunciation: NY-troh-blue tet-RAZ-oh-lee-um
Also written as: NBT — Nitroblue Tetrazolium
A colorimetric assay that assesses neutrophil oxidative burst function by detecting the reduction of yellow NBT dye to blue formazan, used to screen for chronic granulomatous disease.
Full Definition
The nitroblue tetrazolium (NBT) test is a classic functional assay for phagocyte NADPH oxidase activity. Normal neutrophils stimulated by phorbol myristate acetate reduce soluble yellow NBT to an insoluble blue-purple formazan precipitate, indicating intact reactive oxygen species production. Patients with chronic granulomatous disease show absent or severely diminished formazan formation. The NBT test has largely been supplanted by the dihydrorhodamine (DHR) flow cytometry assay in modern laboratories, but it remains referenced in historical and resource-limited-setting literature. Editors must render 'nitroblue tetrazolium' as three unhyphenated words; the acronym NBT is acceptable on subsequent mention.
Usage
Usage note: Always spell out in full on first mention; 'NBT test' is the accepted abbreviated form thereafter. Do not hyphenate.
In Context
- "The nitroblue tetrazolium test yielded a 0% stimulation index, prompting referral for molecular confirmation of chronic granulomatous disease." — Paediatric immunology case report
- "Although the nitroblue tetrazolium test was historically the gold standard, the dihydrorhodamine assay now offers superior quantitative resolution." — Laboratory methods review