 Diagnosis of invasive aspergillosis is often difficult to achieve with certainty, as this requires direct evidence of invasive growth on histopathological examination. A probable diagnosis can be suspected based on both clinical and mycological evidence of the disease, in presence of a susceptible patient. The EORTC-MSG guidelines offer a widely accepted basis for this diagnosis. Under these guidelines, mycological evidence can consist of a positive culture of aspergillus spp, or of detection of galactomannan GM in a relevant body sample. GM is a part of the Aspergillus mould and can be detected using a commercially available immunoenzymatic sandwich microplate assay. However, like most biomarkers, galactomannan is far from a perfect biomarker. Several beta-lactam antibiotics are known to cause false positives, and anti-mould therapy has been reported to significantly lower the sensitivity1. Additional biomarkers that could circumvent these problems would therefore be beneficial. 