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Volume 27, Number 3—March 2021

Systematic Review of Pooling Sputum as an Efficient Method for Xpert MTB/RIF Tuberculosis Testing during the COVID-19 Pandemic

Luis E. CuevasComments to Author , Victor S. Santos, Shirley Verônica Melo Almeida Lima, Konstantina Kontogianni, John S. Bimba, Vibol Iem, Jose Dominguez, Emily Adams, Ana Cubas Atienzar, Thomas Edwards, S. Bertel Squire, Patricia J. Hall, and Jacob Creswell
Author affiliations: Liverpool School of Tropical Medicine, Liverpool, UK (L.E. Cuevas, K. Kontogianni, V. Iem, E. Adams, A.T. Atienzar, T. Edwards, S.B. Squire); Federal University of Alagoas, Arapiraca, Brazil (V.S. Santos); Federal University of Sergipe, Aracaju, Brazil (S.V.M. Almeida Lima); Bingham University, Karu, Nigeria (J.S. Bimba); National TB Control Program, Vientiane, Laos (V. Iem); Institut d'Investigació Germans Trias i Pujol and Universitat Autònoma de Barcelona, Badalona, Spain (J. Dominguez); Centers for Disease Control and Prevention, Atlanta, Georgia, USA (P.J. Hall); Stop TB Partnership, Innovations and Grants, Geneva, Switzerland (J. Creswell)

Main Article

Table 3

Potential cost and time savings and positive and negative effects of pooling in a systematic review of pooling sputum as an efficient method for Xpert MTB/RIF and Ultra testing for tuberculosis during the coronavirus disease pandemic*

Study Cartridge savings Time savings, h (%) Negative effects Positive effects
Model of 1,000 patients with TB prevalence rate of 3% found 67.5% cartridge savings
Lower sensitivity for smear-negative tuberculosis; requires laboratory infrastructure and training
Processes higher volume of samples with fewer materials; time savings
(12) 11% cartridge savings for hospital-based patients 377 (62%) Steps involved heighten potential for errors High-level agreement with individual Xpert results at reduced cost; substantial time savings to process hospital samples

41% cartridge savings for patients identified through active case finding
Higher savings on cartridge cost and processing time for patients identified through active case finding
Improved feasibility and cost-effectiveness of large-scale testing; reduced number of cartridges
Increase in “error” results when using less buffer for pooling compared with standard buffer technique
Reduced costs and number of cartridges
(15) 27% (lower savings estimate using combination of approaches) 226/876 (26%) for all samples; 300/876 (30%) if hybrid approach used NR Method feasible; potential to reduce costs, increase throughput. Pooling can be used selectively if another screening test (e.g., radiograph) used for additional savings (hybrid approach)

34.5% (if used in patients with normal chest x-rays)
Higher savings if only samples from patients without abnormal chest radiographs are included
Method sensitive and cost-effective
*NR, not reported.

Main Article

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Page updated: February 23, 2021
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