Performance of Cryptococcal Antigen Lateral Flow Assay in Bronchoalveolar Lavage Fluid in HIV-Negative Patients

Objective. We presented the performance of cryptococcal antigen lateral flow assay test using bronchoalveolar lavage fluid (BALF) samples in the HIV-negative Chinese population. Methods. From January 2019 to June 2022, cryptococcal antigen was detected in both serum and BALF samples from 113 patients with suspected pulmonary cryptococcosis. Results. 49 patients were finally diagnosed with pulmonary cryptococcosis. The sensitivity of cryptococcal antigen lateral flow assay test in serum and BALF specimens from confirmed cases was 90.0% and 96.0%, respectively, and the specificity was 87.3% and 95.5%, respectively. When the diameter of the lung lesion was less than 15 mm, the antigen positivity rate of BALF was higher than that of serum. Moreover, the result of the cryptococcal antigen test was associated with the lymphocytes count of BALF. Conclusion. Our data demonstrate that cryptococcal antigen Lateral Flow Assay for BALF specimens might contribute to the early diagnosis of pulmonary cryptococcosis.