Limitations of the MTB/RIF Assay: An Xpert Review of 4 Clinical Cases

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The Cepheid Xpert MTB/RIF assay detects Mycobacterium tuberculosis and rifampin resistance but has limitations leading to false results.
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False-positive and false-negative results from the Xpert assay can result in incorrect treatment and increased healthcare costs.
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Confirmatory testing, including culture and phenotypic susceptibility testing, is essential to validate Xpert assay results.
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The review presents four clinical cases illustrating the challenges and discrepancies in TB diagnosis using the Xpert assay.
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Rapid molecular testing is crucial for timely TB diagnosis, especially for multidrug-resistant cases, despite its limitations.

Open Forum Infectious Diseases

by Allison L Haas, Angela Ma, Jonathan Pham, Punam Verma, Uma Malhotra, E Chandler Church, Masahiro Narita, Vincent Escuyer, Salika M Shakir
March 5, 2025

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