Detection of Mycobacterium tuberculosis in urine by Xpert MTB/RIF Ultra: A useful adjunctive diagnostic tool in HIV-associated tuberculosis

Abstract

In January 2017, the World Health Organisation recommended the Xpert® MTB/RIF Ultra assay (Ultra) for tuberculosis (TB) diagnosis. Ultra offers improved analytical sensitivity when compared with the initial Xpert® MTB/RIF (Xpert) assay for the detection of Mycobacterium tuberculosis. Ultra is therefore likely to be of particular benefit for detecting paucibacillary TB.We present a case from Uganda demonstrating Ultra positivity in urine from an HIV-infected patient presenting with altered mental status and urinary incontinence, and no other signs of active pulmonary or extrapulmonary TB. This represents the first published instance of a diagnosis of extrapulmonary TB made on the basis of a positive urine Ultra assay.The use of Ultra on urine may be a useful addition to the diagnostic armamentarium for disseminated TB in persons with HIV co-infection. The diagnostic accuracy of urine Ultra should be characterised further via prospective studies. Keywords: Mycobacterium tuberculosis, Urine, Xpert MTB/RIF Ultra, Renal tuberculosis