BIGG

Lateral flow urine lipoarabinomannan assay (LF-LAM) for the diagnosis of active tuberculosis in people living with HIV. Policy update 2019

Ano de publicação: 2019

The World Health Organization’s (WHO’s) strategy for tuberculosis (TB) prevention, care and control for 2015–2035 (known as the End TB Strategy) prioritizes the early diagnosis of TB. This prioritization includes cases of smear-negative disease, which are often associated with coinfection with HIV and with young age. In 2017, an estimated 0.9 million (9%) of the 10.0 million people who developed TB worldwide were HIV-positive. The WHO African Region accounted for 72% of the estimated number of HIV-positive incident TB cases (2). Tests based on the detection of mycobacterial lipoarabinomannan (LAM) antigen in urine have emerged as potential point-of-care tests for TB. The currently available urinary LAM assays have suboptimal sensitivity, and are therefore not suitable as diagnostic tests for TB in all populations. However, unlike traditional diagnostic methods, urinary LAM assays demonstrate improved sensitivity for the diagnosis of TB among individuals coinfected with HIV. The estimated sensitivity is even greater in patients with lower CD4 cell counts. Currently, the urine lateral flow LAM assay (LF-LAM) strip-test – the Alere Determine™ TB LAM Ag, United States of America (USA), hereafter referred to as AlereLAM – is the only commercially available urinary LAM test. The Global TB Programme convened a Guideline Development Group (GDG) meeting in 2015 to review the evidence for the use of LF-LAM (AlereLAM). The GDG concluded that LF-LAM may be used to assist in the diagnosis of TB only in HIV-positive adults and children with signs and symptoms of TB (pulmonary and/or extrapulmonary) who have a CD4 cell count less than or equal to 100 cells/µL, or HIV-positive patients who are seriously ill1 regardless of CD4 cell count or with unknown CD4 cell count. Since 2015, several studies on the use of AlereLAM assay have been conducted. New evidence has emerged that might justify use of the test in a broader group of patients. In addition, a new urine-based test – the Fujifilm SILVAMP TB LAM, Tokyo, Japan (FujiLAM) – has been developed and preliminary evaluation shows promising results; however, FujiLAM is not yet commercially available