Lateral-Flow Device (LFD) Aspergillus Antigen Detection in Broncho-Alveolar Lavage (BAL) Fluid in Paediatrics: A Literature Review and Pilot Study

Background: Invasive aspergillosis (IA) causes significant morbidity and mortality in immunocompromised children, yet diagnosis remains challenging due to non-specific clinical and radiological findings and the need for invasive procedures. Aspergillus lateral flow devices (Asp-LFD) offer rapid point-of-care testing, particularly for bronchoalveolar lavage (BAL), but paediatric data is limited. Methods: In this study, we combined a literature review and a prospective pilot study to evaluate the use of Asp-LFD in paediatrics. We performed a prospective single-centre study evaluating BAL Asp-LFD in immunocompromised children with suspicion of pulmonary IA. Clinical, radiological, and microbiological data were collected and BAL samples were analysed using the Asp-LFD as well as standard investigations. Results: Paediatric literature review retrieved only one study evaluating serum Asp-LFD which reported low sensitivity (12.1%) but perfect specificity (100%). In contrast, 14 adult studies evaluating Asp-LFD were identified. BAL Asp-LFD sensitivity was reported in 10 studies (71.4%), with a median of 73.0% (min-max: 38–100%), while specificity was reported in nine studies (64.3%) ranged from with a median of 86.0% (min-max: 76–100%). Twenty children were included. Nineteen (95%) received mould-active antifungal therapy before BAL (median: 9 days, IQR 6–16). BAL Asp-LFD was positive in 2/20 patients (10%), without any other evidence of probable or proven IA; conversely, it was negative in one patient classified as having probable IA. BAL culture was negative for moulds in all cases. Conclusions: To our knowledge, this is the first study evaluating BAL Asp-LFD in children. Despite encouraging performance in adults, BAL Asp-LFD demonstrated low positivity in a highly antifungal-pretreated paediatric cohort with delayed sampling. Further paediatric studies with earlier sampling are required to define the role of lateral flow tests.