Table 1.

Pros and Cons of Biological Samples

Type of biosample	Primary use	Storage	Pros	Cons
Whole blood	Generate subfractions (plasma, serum and cells [for extraction, viable storage, or transformation]), and isolate nucleic acids, proteins, and metabolites	Ultra-low temperature with some alternative storage approaches	Wide variety of fractions and analytes. Costs proportional to the number/diversity of tubes drawn and subsequent processing steps	Requires access to −80°C freezer. Need access to phlebotomist
Saliva	Isolate nucleic acids and proteins from host and from the meta-genome	Room temperature for saliva possible; ultra-low temperature for analytes	Ease of collection. Can be done remotely and mailed in	Lack of clinical observation during collection results in minor rate of biospecimen substitution. Quality/quantity of DNA lower than for blood. Contamination of DNA from food etc
Urine	Isolate metabolites.	Ultra-low temperature	24-hour urine collection is standard but processing urine volumes can be challenging	Requires access to −80°C freezer. No DNA.
Buccal Cells	Isolate nucleic acids	Ultra-low temperature.	One tissue type exposed to the environment highly relevant to smoking/vaping behaviors	Care in selecting buccal sampling protocol for comparability