Performance of ultra-sensitive electrochemiluminescence LAM assay for diagnosing tuberculosis in HIV-negative individuals: a multicentre, prospective diagnostic study

PURPOSE: Optimization of urine lipoarabinomannan (LAM) detection platforms holds significant potential for improving early tuberculosis (TB) diagnosis. Currently, accurate urine LAM assays are notably lacking for HIV-negative populations. To address this gap, we evaluated the diagnostic accuracy of an Ultra-sensitive electrochemiluminescence LAM assay (AIMLAM) in HIV-negative individuals with suspected pulmonary TB in Beijing, China. METHODS: In this prospective multicentre study, we enrolled adult (≥ 18 years), presumptive TB patients in Beijing, China. All participants provided sputum samples for smear microscopy, Xpert MTB/RIF assay, and mycobacterial culture, as well as urine samples for AIMLAM testing. Diagnostic performance was evaluated against both microbiological reference standard (MRS) and a composite reference standard (CRS). RESULTS: We collected and stored urine samples from 692 HIV-negative adult presumptive TB patients. Of these, 315 were microbiologically confirmed TB cases, 177 had possible TB, and 200 were considered unlikely to have TB. When evaluated against the MRS, the AIMLAM assay demonstrated a sensitivity of 61.6% (95% CI: 56.1-66.8) and specificity of 83.0% (95% CI: 78.9-86.5). Using the CRS, the AIMLAM assay showed sensitivity 51.6% (95% CI: 47.3-55.9) but specificity 98.0% (95% CI: 94.9-99.4). CONCLUSIONS: The Ultra-sensitive electrochemiluminescence LAM assay demonstrated favorable diagnostic accuracy, potentially offering rapid tuberculosis diagnosis for HIV-negative individuals with pulmonary TB.