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.