Alere Determine-tuberculosis lipoarabinomannan positivity in disseminated non-tuberculous mycobacteria: An illustrative case series

Abstract

Introduction: In outpatients, the World Health Organization recommends that the urine Alere Determine-tuberculosis lipoarabinomannan (AlereLAM) should be used to support the diagnosis of tuberculosis (TB) in people living with HIV (PLHIV) with CD4 counts ≤ 100 cells/µL or with signs of being ‘seriously ill’. There is a risk of a false-positive AlereLAM in disseminated non-tuberculous mycobacterial (NTM) infections and it may be difficult to differentiate a single infection (either Mycobacterium tuberculosis or NTM) from dual infection.

Patient presentation: We report three patients, enrolled in an operational study assessing AlereLAM use in an outpatient setting, who had advanced HIV (all CD4 < 20 cells/µL) and strongly positive (grade 4+) AlereLAM results in whom Mycobacterium avium or kansasii were later cultured from blood or urine and sputum.

Management and outcome: Based on positive AlereLAM results, all three were initiated on TB treatment. One died before NTM infection was detected. Two were managed for dual infection (TB and NTM) but died within two years.

Conclusion: Tuberculosis remains a leading cause of death and a disproportionate number of these deaths occur in PLHIV. Tuberculous treatment should be initiated based on a positive AlereLAM result, and this should be followed by additional testing to confirm the diagnosis of TB and to obtain drug susceptibility results. In those not responding to TB treatment where the only positive result was an AlereLAM, an alternative or additional diagnosis of NTM infection should be considered, particularly in patients with a very low CD4 count.