A systematic review of utility of urine lipoarabinomannan in detecting tuberculosis among HIV-positive tuberculosis suspects.

Sputum smear microscopy (SSM), though regarded as an inexpensive and popular method for detecting tuberculosis (TB), lacks adequate sensitivity, specifically in adult people living with HIV/AIDS (PLHIV). Urine lipoarabinomannan (LAM) is a promising diagnostic tool among PLHIV with CD4 cell count < 200 cells/μl. We attempted to review all the studies undertaken in identifying the utility of urine LAM in diagnosing TB, especially among PLHIV. We searched PubMed, Google Scholar, and MEDLINE databases for studies reporting diagnostic utility of urine LAM status in PLHIV, published in the last 20 years till December 2019. The keywords used for searching were "Tuberculosis," "HIV/AIDS," "Diagnosis," "Screening" "Lipoarabinomannan," and "Urine." Our search resulted in 137 shortlisted citations, of which 67 related manuscripts were identified for detailed study. Based on inclusion and exclusion criteria, 37 studies were reviewed in detail. Average sample size of these studies was 464 (range = 81-2528; SD = 427). Crude average sensitivity of urine LAM in culture-confirmed TB cases was 44.1% (range = 8.3-93) while that of SSM was 38.6% (range = 14-65). However, sensitivity of urine LAM + SSM was 60.4% (range = 38.3-92.7), demonstrating the utility of SSM + urine LAM combination for detecting TB. Specificity was similar between urine LAM and SSM with 92.7% (range = 76-100) and 97.9% (range = 93.9-100), respectively. Majority of the studies demonstrated higher sensitivity of urine LAM in those with lesser the CD4 count, with immunocompromised and with debilitation who cannot produce self-expectorated sputum. We conclude that urine LAM is a potential diagnostic test in the algorithms involving immunocompromised, debilitated patients and specifically in PLHIV whose CD4 count is ≤100 cells/μl.