Digestive enzymes of fungal origin as a relevant cause of false positive Aspergillus antigen testing in intensive care unit patients, Infection

Background: Galactomannan antigen (GM) testing is widely used in the diagnosis of invasive aspergillosis (IA). Digestive enzymes play an important role in enzyme substitution therapy in exocrine pancreatic insufficiency. As digestive enzymes of fungal origin like Nortase contain enzymes from Aspergillus, a false-positive result of the test might be possible because of cross-reacting antigens of the cell wall of the producing fungi. We, therefore, asked whether the administration of fungal enzymes is a relevant cause of false-positive GM antigen test results. Methods: Patients with a positive GM antigen test between January 2016 and April 2020 were included in the evaluation and divided into two groups: group 1 —Nortase-therapy, group 2—no Nortase-therapy. In addition, dissolved Nortase samples were analyzed in vitro for GM and β-1,3-D-glucan. For statistical analysis, the chi-squared and Mann‒Whitney U tests were used. Results: Sixty-five patients were included in this evaluation (30 patients recei ving Nortase and 35 patients not receiving Nortase). The overall false positivity rate of GM testing was 43.1%. Notably, false-positive results were detected significantly more often in the Nortase group (73.3%) than in the control group (17.1%, p
Source: Current Awareness Service for Health (CASH) - Category: Consumer Health News Source Type: news