Non-fumigatus Aspergillus Infection Associated with a Negative Aspergillus Precipitin Test in Patients with Chronic Pulmonary Aspergillosis

Aspergillus antibody testing is key for the clinical diagnosis of chronic pulmonary aspergillosis (CPA) with high sensitivity. However, false-negative results in patients with CPA might be obtained, depending on the Aspergillus species. The aim of this study was to investigate which factors are associated with false-negative results in Aspergillus precipitin tests and whether the sensitivity of precipitin tests in CPA is influenced by Aspergillus fumigatus and non-fumigatus Aspergillus species. Between February 2012 and December 2020, 116 consecutive antifungal treatment-naive patients with CPA were identified and included in this retrospective chart review. Aspergillus species isolated from the respiratory tract of patients were identified by DNA sequencing. Characteristics of patients with positive and negative results for Aspergillus precipitin tests were compared. The sensitivity of the Aspergillus precipitin tests was compared between patients with A. fumigatus-associated CPA and non-fumigatus Aspergillus-associated CPA. A non-fumigatus Aspergillus species was the only factor significantly associated with negative Aspergillus precipitin test results in patients with CPA in the multivariate analysis (hazard ratio, 8.3; 95% confidence interval, 3.2 to 22.1; P < 0.0001). The positivity of the Aspergillus precipitin test for patients with non-fumigatus Aspergillus-associated CPA was lower than that for patients with A. fumigatus-associated CPA (84.8% versus 37.9%; P < 0.0001). These results revealed that the presence of non-fumigatus Aspergillus-associated CPA should be considered with a negative Aspergillus precipitin test; this finding may prevent diagnostic delay or misdiagnosis for CPA.

Automated summary

Aspergillus antibody testing is crucial for diagnosing chronic pulmonary aspergillosis (CPA) with high sensitivity. However, false-negative results may occur depending on the Aspergillus species. This study identified non-fumigatus Aspergillus species as a significant factor associated with negative Aspergillus precipitin test results in CPA patients. The sensitivity of the test was found to be lower in non-fumigatus Aspergillus-associated CPA compared to A. fumigatus-associated CPA.