The Diagnosis of Invasive Aspergillosis by an Enzyme-Linked Immunosorbent Assay for Circulating Antigen

An inhibition enzyme-linked immunosorbent assay (ELISA) capable of detecting 10 ng of aspergillus carbohydrate antigen/ml of serum was developed. When retrospectively applied to the sera of 19 patients with invasive aspergillosis, the ELISA detected antigen in 11 patients. None of 14 healthy controls or 28 patients with a variety of other infections were positive for circulating antigen. A rabbit model of invasive aspergillosis was also developed. Daily fungal cultures of blood were negative in the rabbits, as in human disease, but antigen was detected in increasing amounts up to the time of death. This ELISA is a sensitive, specific, and easily performed assay for circulating aspergillus antigen that should facilitate early diagnosis of invasive aspergillosis, heretofore, seldom made without invasive tests.