The Use of Xpert MTB/RIF Ultra Testing for Early Diagnosis of Tuberculosis: A Retrospective Study from a Single-Center Database

Abstract

Tuberculosis (TB) is a multisystemic contagious disease produced by Mycobacterium tuberculosis complex bacteria (MTBC), with a prevalence of 65:100,000 inhabitants in Romania (six times higher than the European average). The diagnosis usually relies on the detection of MTBC in culture. Although this is a sensitive method of detection and remains the “gold standard”, the results are obtained after several weeks. Nucleic acid amplification tests (NAATs), being a quick and sensitive method, represent progress in the diagnosis of TB. The aim of this study is to assess the assumption that NAAT using Xpert MTB/RIF is an efficient method of TB diagnosis and has the capacity to reduce false-positive results. Pathological samples from 862 patients with TB suspicion were tested using microscopic examination, molecular testing and bacterial culture. The results show that the Xpert MTB/RIF Ultra test has a sensitivity of 95% and a specificity of 96.4% compared with 54.8% sensitivity and 99.5% specificity for Ziehl–Neelsen stain microscopy, and an average of 30 days gained in the diagnosis of TB compared with bacterial culture. The implementation of molecular testing in TB laboratories leads to an important increase in early diagnostics of the disease and the prompter isolation and treatment of infected patients.

Keywords

• tuberculosis
• molecular testing
• Xpert MTB/RIF Ultra
• Ziehl–Neelsen staining
• Lowenstein–Jensen medium culture