Performance of LDBio Aspergillus ICT IgM/IgG Lateral Flow Assay in Diagnosing Chronic Pulmonary Aspergillosis in Community Versus Hospital Setting

Background LDBio immunochromatographic lateral flow assay, a point-of care test, detects IgM/IgG antibodies against Aspergillus fumigatus (LDBio-ALFA). LDBio-ALFA has been evaluated for diagnosing chronic pulmonary aspergillosis (CPA) in hospital patients, though its efficacy in field settings remains unexamined. Objective Our primary objective was to assess the diagnostic accuracy of LDBio-ALFA in diagnosing CPA in a field and a hospital cohort. The secondary objective was to compare the diagnostic performance of LDBio-ALFA and A. fumigatus-IgG measured by a commercial automated fluorescent enzyme immunoassay (FEIA) using latent class analysis (LCA). Methods We prospectively enrolled adult subjects with post-tuberculosis lung abnormality (PTLA) from a tertiary care hospital (hospital cohort), and designated microscopy centers and a community health center (field cohort). We measured A. fumigatus-IgG using LDBio-ALFA and FEIA in the same serum sample. Results We enrolled 508 subjects, of which 122 and 386 constituted field and hospital cohorts. CPA was diagnosed in 325/508 (64%) subjects. The CPA prevalence was higher in the hospital (78% [301/386]) than in the field cohort (19.7% [24/122]). The sensitivity and specificity of LDBio-ALFA in the entire cohort in diagnosing CPA was 81.2% and 85.3%. The sensitivity of LDBio-ALFA in the field cohort was 83.3% and 81.1% in the hospital population. On LCA, the sensitivity and specificity of the FEIA method (A. fumigatus-IgG ≥ 27 mgA/L) was 100% and 86.7%, while for LDBio-ALFA it was for 84.5% and 81.3% for diagnosing CPA. Conclusion LDBio-ALFA is a valuable test for diagnosing CPA in the field and in hospital patients. However, a negative test should be confirmed using an automated immunoassay.