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
(11)	Model of 1,000 patients with TB prevalence rate of 3% found 67.5% cartridge savings	NR	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	NR	NR	Higher savings on cartridge cost and processing time for patients identified through active case finding
(13)	NR	NR	NR	Improved feasibility and cost-effectiveness of large-scale testing; reduced number of cartridges
(14)	NR	NR	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)	NR	NR	Higher savings if only samples from patients without abnormal chest radiographs are included
(10)	NR	NR	NR	Method sensitive and cost-effective
*NR, not reported.