NEW CAUSE FOR FALSE-POSITIVE RESULTS WITH THE PASTOREX ASPERGILLUS ANTIGEN LATEX AGGLUTINATION-TEST

The Pastorex Aspergillus antigen test for detection of Aspergillus gal actomannan antigen in the sera of patients with invasive aspergillosis is used in many clinical laboratories. A serum sample contaminated wi th Penicillium chrysogenum gave a strongly positive reaction (1:128) w hich was heat stable, was not eliminated by pronase treatment, and was not detected by a normal rabbit globulin control. This observation wa s shown to be due to cross-reactions of the monoclonal antibody EB-A2 used by the kit with several airborne fungi likely to contaminate seru m samples, including Penicillium chrysogenum, Cladosporium herbarum, A cremonium species, Alternaria alternata, Fusarium oxysporum, Wangiella dermatitidis, and Rhodotorula rubra.