Antigen tests are rapid assays that enable early screening of opportunistic infections in people living with HIV (PLHIV). This study aimed to assess the prevalence and performance of tests for disseminated histoplasmosis (DH) and tuberculosis (TB) in PLHIV, between 2023 and 2024, in a referral hospital in northeastern Brazil.

Prevalence study including patients who underwent lateral flow antigen tests for DH screening through detection of urinary Histoplasma capsulatum galactomannan antigen (LF-AgHc, Miravista®) and for TB through detection of urinary lipoarabinomannan antigen (LF-LAM, Abbott). We included PLHIV >18 years of age with CD4 < 200 cells/mm³ or World Health Organization clinical stage 3 or 4, as well as PLHIV with treatment interruption.

During the study period, 244 hospitalized patients and 97 outpatients were screened for DH and TB. Most were cisgender men. The mean age was 40 years and mean CD4+ count was 104 cells/mm³. Overall DH prevalence was 12.2%; however, among hospitalized patients, prevalence was higher than among outpatients (14.75% vs. 5.15%; p < 0.005). When evaluating LF-AgHc performance against leukocyte concentrate culture (n = 101), sensitivity was 85%, specificity 88.9%, positive predictive value (PPV) 65.4%, negative predictive value (NPV) 96%, and kappa index 0.663. Among patients with reactive LF-AgHc only (n = 24/41), 83.3% received antifungal treatment for probable DH. Regarding LF-LAM, overall TB prevalence was 11.3%, similar in hospitalized and outpatient groups (11.57% vs. 10.71%; p > 0.05). Compared with the Rapid Molecular Test for TB (TRM-TB; n = 143), LF-LAM sensitivity was 40.5%, specificity 94.3%, PPV 71.4%, NPV 82%, and kappa 0.630. Among patients with reactive LF-LAM only (n = 21/36), 90.5% were treated for TB. Death occurred in 22% of patients with positive LF-AgHc and in 5.8% of those with reactive LF-LAM.

The high prevalence of DH among hospitalized patients reinforces the need for early screening in this population. For tuberculosis, confirmatory testing with TRM-TB is important to establish the diagnosis of pulmonary TB, given the low sensitivity of LF-LAM. It is worth noting the high mortality in PLHIV with DH when compared to TB.