Detection of Mycobacterium tuberculosis in paucibacillary sputum : performances of the Xpert MTB/RIF ultra compared to the Xpert MTB/RIF, and IS6110 PCR Kolia-Diafouka, P. Carrere-Kremer, S. /Lounnas, Manon Bourdin, A. Kremer, L. Van de Perre, P. Godreuil, S. Tuaillon, E. Chelex (R) Mycobacterium tuberculosis IS6110-PCR Xpert MTB/RIF Xpert MTB/RIF ultra Paucibacillary sputum The Xpert MTB/RIF Ultra assay has recently been launched to improve the detection of smear negative disease. This retrospective study compares the sensitivity of Xpert MTB/RIF Ultra with that of Xpert MTB/RIF tests and IS6110 real-time PCR in sputum. Diagnostic performance of three molecular tests was evaluated using 48 culture-positive clinical respiratory specimens diluted to obtain paucibacillary sputum specimens. Xpert MTB/RIF Ultra had the highest sensitivity of 100% compared to 42% (P < 0.001) for Xpert MTB/RIF and 64.5% (P = 0.02) for IS6110-PCR. All "very low" or "low" positive specimens using Xpert MTB/RIF Ultra were tested positive using IS6110-PCR, but 35.4% were found negative using Xpert MTB/RIF. Xpert MTB/RIF Ultra is more sensitive than the two other tests for sputum with a low bacterial load. Adding detection of IS6110 and IS1081 to rpoB, is a key evolution of the assay and improves the detection of Mycobacterium tuberculosis' DNA in paucibacillary sputum. 2019 text https://www.documentation.ird.fr/hor/fdi:010076533 fdi:010076533 Kolia-Diafouka P., Carrere-Kremer S., Lounnas Manon, Bourdin A., Kremer L., Van de Perre P., Godreuil S., Tuaillon E.. Detection of Mycobacterium tuberculosis in paucibacillary sputum : performances of the Xpert MTB/RIF ultra compared to the Xpert MTB/RIF, and IS6110 PCR. 2019, 94 (4), 365-370 EN