Evaluation of Two Lateral Flow Assays in BAL Fluids for the Detection of Invasive Pulmonary Aspergillosis: A Retrospective Two-centre Study

Background: Commonly, the application of radiological and clinical criteria and the determination of galactomannan (GM) in respiratory samples are used as a diagnostic tool for the detection of invasive pulmonary aspergillosis (IPA).

Materials/methods: In this study, two lateral flow assays, OLM Aspergillus lateral flow device (LFD) and IMMY sōna Aspergillus Galactomannan lateral flow assay (LFA), were evaluated at two tertiary hospitals in Germany. A total of 200 bronchoalveolar lavage (BAL) samples from patients with suspicion of IPA were analysed retrospectively. LFD and LFA were evaluated against four different criteria: Blot, EORTC/MSG, Schauwvlieghe and extended Blot criteria and additionally against GM.

Results: The evaluation of four algorithms for the diagnosis of IPA showed that there exist good diagnostic tools to rule out an IPA even before results of Aspergillus culture are available. Sensitivities and negative predictive values are generally higher for the LFA than for the LFD in all four criteria. Specificity and positive predictive values varied depending on the classification criteria. The total agreement between the GM and the LFA cube reader (cut-off = 1) was 84%. The correlation between the GM and LFA was calculated with r = 0.8.

Conclusion: The here presented data indicate that a negative LFA result in BAL fluid can reliable rule out an IPA in a heterogeneous group of ICU patients based on the original Blot criteria. LFA seems to be a promising immunochromatographic test exhibiting a good agreement with positive GM values.