ABSTRACT

Background: the diagnosis of tuberculosis has been revolutionized in the last decade with the introduction of rapid molecular tests for species identification and drug resistance. Material and methods: the Xpert^®MTB/RIF database of the Tijuana General Hospital and Tuberculosis Laboratory was analyzed for a period of three years, selecting the cases that also had smear microscopy and culture for tuberculosis. Results: There were 283 consecutive tests of Xpert^®MTB/RIF, of which 192 also had culture results. The sensitivity of Xpert^®MTB/RIF in smear positive patients (≥ 1+) was 94%; in patients with positive but with scant bacilli (quantified in bacilli per 100 and 200 fields), the sensitivity was 89.2%. The Xpert^®MTB/RIF was positive in 93 of the 104 patients with positive culture for MTB (overall sensitivity of Xpert^®MTB/RIF versus culture: 89.4%). Conclusions: The Xpert MTB/RIF is a highly reproducible test under programmatic conditions and should replace microscopy according to the recommendations of the World Health Organization as an initial test in patients with suspected drug-resistant tuberculosis and comorbidity due to HIV.

KEYWORDS

Xpert^®MTB/RIF, tuberculosis, drug-resistance, diagnosis.

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