The use of lateral flow urine lipoarabinomannan assay (‎LF-LAM)‎ for the diagnosis and screening of active tuberculosis in people living with HIV: policy guidance

Overview

Background

Tests based on the detection of mycobacterial lipoarabinomannan (LAM) antigen in urine have emerged as potential point-of-care tests for tuberculosis (TB). LAM antigen is a lipopolysaccharide present in mycobacterial cell walls, which is released from metabolically active or degenerating bacterial cells and appears to be present only in people with active TB disease. Urine-based testing would have advantages over sputum-based testing because urine is easy to collect and store, and lacks the infection control risks associated with sputum collection.

Objectives

This document provides a summary of the evidence and recommendations for the use of LF-LAM for the diagnosis and screening of active tuberculosis in people living with HIV.

• To assess the available data on the accuracy (sensitivity and specificity) of lateral flow urine lipoarabinomannan assay (LF-LAM) for screening and diagnosis of active TB in HIV-infected adults, at different thresholds for test positivity, as a replacement or in combination with other diagnostic tools.
• To assess the available data on the accuracy (sensitivity and specificity) of lateral flow urine lipoarabinomannan assay (LF-LAM) for diagnosis of active TB in HIV-infected children.
• To assess data related to patient outcomes, both the association of LAM positivity and patient outcomes and the impact of LAM implementation on patient outcomes in HIV-infected patients, as a replacement or in combination with other diagnostic tools.
• To assess available data on the cost, and cost-effectiveness of LAM implementation for TB diagnosis or screening of active tuberculosis in people living with HIV compared with sputum microscopy or Xpert MTB/RIF.
• To develop WHO policy recommendations for the appropriate use of LF-LAM for the diagnosis and screening of active tuberculosis in people living with HIV.