The acridine orange fluorochrome microassay: a new technique for quantitation of neutrophil function in burned...

A new assay for determination of neutrophil bacterial killing and phagocytosis is presented. The acridine orange (AO) fluorochrome microassay is a simple, reliable technique for assessing polymorphonuclear (PMN) function. It requires small amounts of blood and provides a rapid and reproducible quantitation of neutrophil activity. Using this technique, bacterial killing and phagocytosis were assessed in a group of five severely burned patients admitted to the Medical College of Virginia Burn Unit. All patients studied demonstrated a significant decrease in bacterial killing at some point during their clinical course. The AO assay was found to be a reliable and effective means of quantitating PMN bacterial phagocytosis and killing in this group of burned patients.