Combination of urinary lipoarabinomannan assay and GeneXpert MTB/RIF ultra enhances tuberculosis detection among HIV-infected individuals

Background: Tuberculosis (TB) is a major health concern, responsible for about 10 million morbidities and 1.3 million global deaths, of which 300,000 are HIV co-infected. Timely diagnosis and treatment of TB have saved millions of lives. Lipoarabinomannan (LAM) assays and GeneXpert MTB/RIF Ultra have greatly altered TB diagnosis, but information on their performance in terms of accuracy, efficiency and turnaround time is limited. This analytic cross-sectional study investigated the diagnostic accuracy of urinary LAM and GeneXpert MTB/RIF Ultra in TB detection among adult HIV-positive individuals receiving care at Kisii Teaching and Referral Hospital. Methods: Participants (n=372) were enrolled from facility Xpert testing log, where all patients with Xpert-positive results were recruited. Results: There was variation in sensitivity between AlereLAM (10.8%), FujiLAM (53.2%), and EclLAM (66.7%), and generally high specificities: AlereLAM (92.3%), FujiLAM (98.9%), and EclLAM (98.1%). GeneXpert MTB/RIF Ultra had a 90.5% sensitivity and 98.1% specificity, without significant difference in sensitivity or specificity by previous TB history, hospitalization, or HIV status. Xpert and GeneXpert MTB/RIF Ultra results were concordant, with the latter showing a small reduction in specificity (difference 1.9; p=0.01). Considering trace results as positive for all cases increased sensitivity by 2.1% (p=0.01) without reduction in specificity (p=0.08). Conclusions: FujiLAM and GeneXpert MTB/RIF Ultra have the capacity to improve TB diagnosis, especially in HIV-positive individuals and in high-burden settings, with enhanced sensitivity and specificity. Integrating these assays can boost prompt treatment initiation and better patient outcomes, although further research is needed.