Tubes and vials for general collection, storage, and transportation of samples; available in a variety of colors, sizes, volume capacities, and material compositions; may be sterile, non-sterile, and/or autoclavable; may include caps.

The term “vial” is somewhat undefined and is usually described as a small, cylindrical, and flat-bottomed container used to hold liquids. Most sample vials are made of plastic or glass, and include a separate or attached lid or closure. Sample vials are categorized by material and also by their size or specific purpose.

Glass sample vials are categorized by the type of glass used to make them.

• Type I, Class A glass sample vials are made from low-expansion borosilicate glass
• Type I, Class B glass sample vials are made from an alumino-borosilicate glass
• Type II are made from soda-lime glass

Plastic sample vials may be made from a variety of resins, including:

• Polycarbonate
• Polypropylene
• Polystyrene
• Low-density polyethylene (LDPE)
• High-density polyethylene (HDPE)

Glass sample vials may be clear or amber-colored (to protect the contents from ultraviolet light). Plastic sample vials are available in a range of colors, including amber, natural, and clear resins.

Sample vials may have different types of closures, depending on their use and the material being stored.

• Screw caps
• For both glass and plastic sample vials
• May be closed or open
• Typically made from polypropylene or phenolic resin (with a variety of closure liners, including PE foam, PTFE, cork, tin, etc.)
• Flip-top
• Caps for plastic sample vials may be attached by a tether to the vial itself
• Also called “captive” closures
• Snap caps (external): Both glass and plastic sample vials
• Plug caps (internal): Both glass and plastic sample vials