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