USE OF THE PASTOREX ASPERGILLUS ANTIGEN LATEX AGGLUTINATION-TEST FOR THE DIAGNOSIS OF INVASIVE ASPERGILLOSIS

Aims-To evaluate the Pastorex aspergillus antigen latex agglutination test for the diagnosis of invasive aspergillosis in patients undergoin g liver or bone marrow transplantation. Methods-Serum samples were tak en at least twice weekly post-transplant and tested for Aspergillus an tigen. Latex agglutination test results were compared with microbiolog ical examination of respiratory, urine and bile specimens. Serum sampl es from liver transplant patients were also tested for antibodies to A spergillus fumigatus by counter immunoelectrophoresis. Results-Eight o f the 91 patients studied developed invasive aspergillosis. Positive l atex agglutination tests were obtained in eight of 187 (4.3%) serum sa mples from four of these eight patients. The other four patients with invasive aspergillosis gave consistently negative latex agglutination tests. A positive latex agglutination test was the first indication of invasive aspergillosis in two patients; these patients were already o n amphotericin B. Positive latex agglutination tests were the only evi dence of invasive aspergillosis in one patient who subsequently died o f the infection. False positive latex agglutination tests were obtaine d in five of 83 (6%) patients with no evidence of invasive aspergillos is and misleading positive cultures seen in nine of 83 (10.8%). No ant ibodies were detected in three of four liver transplant patients with invasive aspergillosis. Conversely, antibodies were detected in 63 of 262 (24%) serum samples from 43 Liver transplant patients with no evid ence of invasive aspergillosis; one of these patients had an antibody titre of 1:2 on four separate occasions. Conclusions-The Pastorex aspe rgillus antigen latex agglutination test, when used alone, lacks sensi tivity and specificity for the early diagnosis of invasive aspergillos is. A diagnosis was made in all patients with invasive aspergillosis w hen both culture and antigen tests were performed although using these criteria a false positive diagnosis would have been made in 13 of 83 (15.6%) patients. Microbiological and serial serological investigation s for antigen should both be performed and the results considered in c onjunction with radiological and clinical evidence.