Comparative analysis of galactomannan lateral flow assay, galactomannan enzyme immunoassay and BAL culture for diagnosis of COVID-19-associated pulmonary aspergillosis.

Abstract

BackgroundGalactomannan Enzyme Immunoassay (GM‐EIA) is proved to be a cornerstone in the diagnosis of COVID‐19‐associated pulmonary aspergillosis (CAPA), its use is limited in middle and low‐income countries, where the application of simple and rapid test, including Galactomannan Lateral Flow Assay (GM‐LFA), is highly appreciated. Despite such merits, limited studies directly compared GM‐LFA with GM‐EIA. Herein we compared the diagnostic features of GM‐LFA, GM‐EIA and bronchoalveolar lavage (BAL) culture for CAPA diagnosis in Iran, a developing country.Materials/MethodsDiagnostic performances of GM‐LFA and GM‐EIA in BAL (GM indexes ≥1) and serum (GM indexes >0.5), i.e. sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) and areas under the curve (AUC), were evaluated using BAL (n = 105) and serum (n = 101) samples from mechanically ventilated COVID‐19 patients in intensive care units. Patients were classified based on the presence of host factors, radiological findings and mycological evidences according to 2020 ECMM/ISHAM consensus criteria for CAPA diagnosis.ResultsThe Aspergillus GM‐LFA for serum and BAL samples showed a sensitivity of 56.3% and 60.6%, specificity of 94.2% and 88.9%, PPV of 81.8% and 71.4%, NPV of 82.3% and 83.1%, when compared with BAL culture, respectively. GM‐EIA showed sensitivities of 46.9% and 54.5%, specificities of 100% and 91.7%, PPVs of 100% and 75%, NPVs of 80.2% and 81.5% for serum and BAL samples, respectively.ConclusionOur study found GM‐LFA as a reliable simple and rapid diagnostic tool, which could circumvent the shortcomings of culture and GM‐EIA and be pivotal in timely initiation of antifungal treatment.