Stimulated nitroblue tetrazolium test to assess neutrophil antibacterial function: Prediction of wound sepsis in burned patients

Neutrophil bactericidal function, as measured by the in vitro stimulated reduction of nitroblue tetrazolium (NBT), was compared with semiquantitative wound biopsy cultures as a means of predicting and diagnosing incipient sepsis in burn patients. Leukocytes from 30 patients with greater than 30% total body surface burns were studied serially during the first month of hospitalization. Phagocytic function was unaltered in patients with sepsis as compared to uninfected patients and unburned controls. However, stimulated NBT reduction in any single patient was significantly inhibited either prior to coincident with increased bacterial wound colonization. A stimulated NBT value of less than 50% of the patient's admission value was nearly uniformly associated with burn wound sepsis (greater than 10⁵ organisms per gram of tissue), whereas a stimulated NBT value of greater than 90% of the patient's admission value was indicative of only modest wound colonization. The results suggest that the stimulated NBT reduction test may provide an inexpensive and rapid means of monitoring wound colonization in burned patients, resulting in more timely treatment of septic complications.