TY - JOUR
T1 - Performance of Xpert MTB/RIF, Xpert Ultra, and Abbott RealTime MTB for diagnosis of pulmonary tuberculosis in a high-HIV-burden setting
AU - Berhanu, Rebecca H.
AU - David, Anura
AU - da Silva, Pedro
AU - Shearer, Kate
AU - Sanne, Ian
AU - Stevens, Wendy
AU - Scott, Lesley
N1 - Funding Information:
Cepheid provided the Xpert MTB/RIF and Ultra test kits free of charge. R.B. and K.S. received research support from the National Institute of Health Fogarty International Center (grant no. D43TW009340 to R.H.B. and no. R25TW009340 to K.S.). L.S. and W.S. received research support from the U.K./South Africa Newton Fund (no. 015NEWTONTB).
Funding Information:
We thank the staff at Witkoppen Health and Wellness Centre, Helen Joseph TB Focal Point, and Hillbrow Community Health Centre and Matilda Nduna and Lebohang Ngolele for their contributions to this study. Cepheid provided the Xpert MTB/RIF and Ultra test kits free of charge. R.B. and K.S. received research support from the National Institute of Health Fogarty International Center (grant no. D43TW009340 to R.H.B. and no. R25TW009340 to K.S.). L.S. and W.S. received research support from the U.K./South Africa Newton Fund (no. 015NEWTONTB). The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication. W.S. and L.S. declare that they have received funding for a number of TB assay validations in the form of reagents from different diagnostic companies (Cepheid, Abbott, Roche, Hain Lifesciences, DNA Genotek, and Alere). W.S. declares that a family member is employed by Cepheid in South Africa.
Publisher Copyright:
© 2018 American Society for Microbiology. All Rights Reserved.
PY - 2018/12
Y1 - 2018/12
N2 - More sensitive tests are needed for the diagnosis of smear-negative and HIV-associated tuberculosis. This study compares the sensitivities and specificities of three molecular tests, namely, the Xpert MTB/RIF test, the Xpert Ultra (Ultra), and RealTime MTB (RT-MTB), in a high HIV prevalence setting. Symptomatic adults were recruited from three outpatient sites, and each provided 4 sputum specimens. The diagnostic performance of Xpert MTB/RIF, Ultra, and RT-MTB was evaluated, with culture as a reference standard. HIV infection occurred in 62% of patients, with a median CD4 count of 220 cells/l. The Ultra test had the highest sensitivity of 89.3% (95% confidence interval [CI], 78.1 to 96) compared to those of the Xpert MTB/RIF at 82.1% (95% CI, 69.6 to 91.1; P 0.12) and RT-MTB at 78.6% (95% CI, 65.6 to 88.4; P 0.68). The specificity was highest with the Xpert MTB/RIF at 100% (95% CI, 98 to 100), followed by RealTime MTB at 96.7% (95% CI, 92.9 to 98.8; P 0.03) and the Ultra at 95.6% (95% CI, 91.5 to 98.1; P 0.08). In patients with smear-negative disease, the Ultra was more sensitive than the Xpert MTB/RIF (64.7% [95% CI, 38.3 to 85.8] versus 41.2% [95% CI, 18.4 to 67.1], respectively; P 0.12), and RT-MTB performed equally to Xpert MTB/RIF. In a comparison of the Ultra and RT-MTB on the same sputum specimen pellets, the Ultra was more sensitive than RT-MTB in the overall cohort (88.9% [95% CI, 77.4 to 95.8] versus 77.8% [95% CI, 64.4 to 88], respectively; P 0.03) and among people with HIV (87.5% [95% CI, 71 to 96.5] versus 68.6% [95% CI, 50 to 83.9], respectively; P 0.03). Although these results did not reach statistical significance, they suggest that the Ultra is more sensitive than the Xpert MTB/RIF and RT-MTB, most prominently in smear-negative disease. This was accompanied by a loss of specificity.
AB - More sensitive tests are needed for the diagnosis of smear-negative and HIV-associated tuberculosis. This study compares the sensitivities and specificities of three molecular tests, namely, the Xpert MTB/RIF test, the Xpert Ultra (Ultra), and RealTime MTB (RT-MTB), in a high HIV prevalence setting. Symptomatic adults were recruited from three outpatient sites, and each provided 4 sputum specimens. The diagnostic performance of Xpert MTB/RIF, Ultra, and RT-MTB was evaluated, with culture as a reference standard. HIV infection occurred in 62% of patients, with a median CD4 count of 220 cells/l. The Ultra test had the highest sensitivity of 89.3% (95% confidence interval [CI], 78.1 to 96) compared to those of the Xpert MTB/RIF at 82.1% (95% CI, 69.6 to 91.1; P 0.12) and RT-MTB at 78.6% (95% CI, 65.6 to 88.4; P 0.68). The specificity was highest with the Xpert MTB/RIF at 100% (95% CI, 98 to 100), followed by RealTime MTB at 96.7% (95% CI, 92.9 to 98.8; P 0.03) and the Ultra at 95.6% (95% CI, 91.5 to 98.1; P 0.08). In patients with smear-negative disease, the Ultra was more sensitive than the Xpert MTB/RIF (64.7% [95% CI, 38.3 to 85.8] versus 41.2% [95% CI, 18.4 to 67.1], respectively; P 0.12), and RT-MTB performed equally to Xpert MTB/RIF. In a comparison of the Ultra and RT-MTB on the same sputum specimen pellets, the Ultra was more sensitive than RT-MTB in the overall cohort (88.9% [95% CI, 77.4 to 95.8] versus 77.8% [95% CI, 64.4 to 88], respectively; P 0.03) and among people with HIV (87.5% [95% CI, 71 to 96.5] versus 68.6% [95% CI, 50 to 83.9], respectively; P 0.03). Although these results did not reach statistical significance, they suggest that the Ultra is more sensitive than the Xpert MTB/RIF and RT-MTB, most prominently in smear-negative disease. This was accompanied by a loss of specificity.
KW - Abbott RealTime MTB
KW - Molecular diagnostics
KW - South Africa
KW - Tuberculosis
KW - Xpert MTB/RIF
KW - Xpert Ultra
UR - http://www.scopus.com/inward/record.url?scp=85057268235&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85057268235&partnerID=8YFLogxK
U2 - 10.1128/JCM.00560-18
DO - 10.1128/JCM.00560-18
M3 - Article
C2 - 30305387
AN - SCOPUS:85057268235
SN - 0095-1137
VL - 56
JO - Journal of Clinical Microbiology
JF - Journal of Clinical Microbiology
IS - 12
M1 - e00560-18
ER -