Diagnostic value of the serum galactomannan assay for invasive aspergillosis: it is less useful in non-haematological patients

Abstract

BACKGROUND: The serum galactomannan assay (GMA) has been widely used for the diagnosis of invasive aspergillosis (IA). GMA is mainly used in patients with haematological malignancies or in those who have undergone haematopoietic stem cell transplantation (HSCT). However, there are few data from non-haematological patients. We evaluated whether GMA is useful for the diagnosis of IA in non-haematological patients.

METHODS: Patients who were subjected to serum GMA testing from January 2007 to December 2009 were evaluated retrospectively. Patients with haematological diseases or who underwent HSCT were excluded from our analysis. According to the criteria of the European Organization for Research and Treatment of Cancer/Mycoses Study Group revised in 2008, the patients were categorized as proven, probable, possible, or non-IA. Proven and probable cases were defined as IA in this study.

RESULTS: Out of 778 patients, 13 (1.6%) had proven (n =9) or probable (n =4) IA. The sensitivity of the GMA was 23.1% (95% confidence interval (CI) 6.1-54.0%) and the specificity was 76.1% (95% CI 72.9-79.0%). The positive predictive value was 1.6% (95% CI 0.4-5.0%) and the negative predictive value was 98.3% (95% CI 96.8-99.1%). The likelihood ratios of a positive and negative test were 0.96 (95% CI 0.35-2.62) and 1.01 (95% CI 0.75-1.36), respectively.

CONCLUSIONS: In this study, the sensitivity of the GMA for the diagnosis of IA was very low in non-haematological patients. Although the GMA test is considered useful for the diagnosis of IA in haematological patients, it had low diagnostic value for IA in non-haematological patients.