Chronic pulmonary aspergillosis (CPA) is a significant complication in post-tuberculosis (TB) patients, requiring accurate diagnosis for effective management. LD-Bio Immunochromatography (ICT) and Aspergillus IgG Enzyme-Linked Immunosorbent Assay (ELISA) are commonly used to detect Aspergillus infections. This observational analytic study, employing a cross-sectional design, was conducted among post-TB patients at Dr. Saiful Anwar General Hospital in East Java, Indonesia. Patients who met the criteria for probable CPA underwent sputum culture, Aspergillus IgG ELISA, and LD Bio ICT testing. The sensitivity and specificity of LD Bio ICT and Aspergillus IgG ELISA were evaluated using 2 × 2 tables in two separate analyses: one using probable CPA diagnosis as the reference, and another using sputum culture as an independent comparator. Twenty-nine patients were included, with 16 classified as probable CPA and 13 as non-probable CPA. LD-Bio ICT showed 75% sensitivity, 92.31% specificity, 92.31% positive predictive value, 75% negative predictive value, and 82.76% accuracy. In comparison, ELISA had a sensitivity of 50%, a specificity of 76.92%, a positive predictive value of 72.73%, a negative predictive value of 55.56%, and an accuracy of 62.07%. Sputum culture had 100% specificity and 31.25% sensitivity, with an overall accuracy of 62.07%. LD-Bio ICT outperforms the Aspergillus IgG ELISA in terms of sensitivity, specificity, and accuracy in diagnosing CPA in post-TB patients. © 2025 by the author(s).