TABLE 3.

Comparison of buffers for preservation of RNA viruses in fecal samples

Buffer	Manufacturer	Cost per mL	Fecal sample-to-buffer ratio (mg:mL)	Time shelf stable (at 25°C)	Percent yield (high concentration, Week 4)	Considerations	Examples of use in previous studies
DNA/RNA Shield	Zymo	~$1.90	100:1	>30 days	85.7%	Incompatible with some non-Zymo kits and workflows.	(15)
RNAlater	Thermo Fisher	~$1.10	200:1	1 week	50.0%	Usable with most commercially available kits and workflows.	(16, 17)
Viral Transport Medium	a	~$0.30	1,000:1	Not shelf stable	20.9%	Samples must be frozen.	(15, 18)
95% Ethanol	a	<$0.10	1,000:1	Indefinitely	0.1%	Shelf stable for DNA, but not shelf stable for RNA.	(19)

^a Available from multiple manufacturers.