Galactomannan detection in nonserum specimens: Where do we stand?

Abstract

Aspergillus species have emerged as a cause of devastating infections in immunocompromised patients. A circulating antigen in aspergillosis is galactomannan (GM), a cell wall constituent released during growth. GM can be detected in serum of neutropenic patients at an early stage of disease, often before clinical signs become apparent. Until recently, data regarding performance of the test in other fluids were lacking. It was suggested that, in absence of neutropenia, viable fungi can endure in lung tissue, whereas circulating markers remained undetectable because of clearance by circulating neutrophils. Indeed, bronchoalveolar lavage (BAL) fluid proved to be a better specimen for the diagnosis of invasive aspergillosis in critically ill patients. The published clinical experience with GM in BAL fluid in solid organ transplant recipients also showed promising results. The evidence for using GM in other body fluids, such as cerebrospinal fluid and urine, is based on case reports. The objective of this review is to summarize the current evidence for GM detection in nonserum fluids.