Diagnostic and prognostic utility of urine LF-LAM assay for tuberculosis detection in advanced HIV

Background: The diagnostic tests available for TB are very accurate but samples are yield dependent. WHO recommends the use of LF LAM for diagnosis of active TB in patients with advanced HIV disease. Material and Methods: This cross-sectional validity study was conducted at the Infectious Diseases Department of the Pakistan Institute of Medical Sciences, a large public-sector tertiary care hospital in Pakistan, from October to December 2024. A total of 113 patients with advanced HIV disease were enrolled in this study. The patients underwent Xpert MTB Ultra and LF LAM. These patients were followed for 8 weeks to assess survival. Results: There were 99(87.6%) males and 14(12.4%) females of total 113 patients. The number of patients who survived and those who did not survive at 8 weeks was 88(77.9%), and 25 (22.1%) respectively. The LF LAM was found to have sensitivity (76.1%), Specificity (86.1%), PPV (87.27%), NPV (74.13%), and LR+ (5.42). The Discion tree analysis showed that positive LF LAM leads to the probability of 76.3% survival. The age (OR 0.946; 95%CI 0.905-0.978; p=0.012), Xpert MTB Ultra (OR 14.288; 95%CI 2.24-91.05; p=0.005), TB LAM (OR 0.416;95% CI 0.034-0.842; p=0.030) were found to be significant predictors of survival at 8 weeks. Conclusion: LF LAM is a promising diagnostic strategy with good prognostic value in patients with HIV/TB coinfection. Keywords: Diagnostic accuracy, Decision tree, LF LAM, Xpert MTB ultra