BRIEF COMMUNICATIONS The Nitroblue Tetrazolium Test and Acute Myocardial Infarction A Study in Patients

The nitroblue tetrazolium dye test was evaluated in 16 patients with acute myocardial infarction, a stressful, noninfectious disease. All subjects had positive tests during the acute phase of their illness. Over a 2-week period the values fell into the control range in 7 of 10 patients who were serially tested. Three patients who developed complications had persistently positive tests. There was no correlation between the test and fever, total leukocyte count, or myocardial enzyme values. Anticoagulant therapy did not seem to affect the results. Neutrophil activation was thus shown in patients with acute myocardial infarction. This activation was related to the age of the infarction and seemed to correlate with the stages of maximal neutrophilic infiltration in the damaged areas. THE NITROBLUE TETRAZOLIUM TEST has been advo-cated to diagnose bacterial infections in vivo (1). In vitro, normally, few neutrophils reduce the nitroblue tetrazolium dye spontaneously. During phagocytosis, however, large numbers of peripheral blood neutro-phils will reduce the dye (2, 3). Difficulties have arisen in the interpretation of the test. The test can be falsely negative, that is, few neu-trophils reduce the dye in the face of active bacterial infection (4). False-positive tests have also been de-scribed, in which large numbers of neutrophils reduce the dye in the absence of bacterial infection (5). Be-cause of these discrepancies, the specificity of the test was examined in patients with acute myocardial infarction, an acute process characterized by fever, an increased sedimentation rate, slight leukocytosis, and a relatively low incidence of associated infection