Comparison of a novel Aspergillus lateral-flow device and the Platelia® galactomannan assay for the diagnosis of invasive aspergillosis following haematopoietic stem cell transplantation.

PURPOSE: The detection of galactomannan in serum is a cornerstone for the diagnosis of invasive fungal disease (IFD). Because a delay in treatment initiation is associated with a poor outcome, the results have to be available promptly. However, due to methodological and economic reasons, the test frequencies of the commonly used galactomannan assays vary between daily to weekly, meaning that results may be available too late to be clinically useful. The novel Aspergillus lateral-flow device (Aspergillus-LFD) is a rapid test that may overcome these limitations.

METHODS: We compared the diagnostic performance of the Aspergillus-LFD and the Platelia® Aspergillus EIA (GM-EIA) in serum from 101 patients during and after allogeneic haematopoietic stem cell transplantation (HSCT). Clinical data and sera were collected prospectively and patients classified according to the European Organisation for Research and Treatment of Cancer (EORTC)/Mycoses Study Group (MSG) 2008 guidelines.

RESULTS: By the end of hospitalisation, one proven, nine probable and 20 possible cases of IFD were identified. Depending on the number of positive serum samples required for test positivity, the sensitivities, specificities and diagnostic odds ratios in patients with proven and probable IFD were as follows. One positive serum required: Aspergillus-LFD 40.0 %, 86.8 % and 3.03; GM-EIA 40.0 %, 89.0 % and 3.64. Two positive sera required: Aspergillus-LFD 20.0 %, 97.8 % and 11.13; GM-EIA 30.0 %, 98.9 % and 38.57. Although the GM-EIA was positive in a higher percentage of samples, this did not result in an earlier diagnosis.

CONCLUSIONS: If used as a screening test (one positive serum required for test positivity) or to rule out IFD, the Aspergillus-LFD has shown a comparable diagnostic performance to the GM-EIA. However, if the results have to be confirmed by a second positive serum, the GM-EIA exhibited superior sensitivity. In terms of practicability, the Aspergillus-LFD has demonstrated to be a quick (15 min) and easy-to-use test for single-patient detection of Aspergillus antigens.