A cryogenic tube, also referred to as a cryotube or cryogenic storage tube, is a laboratory vessel engineered for the preservation, transport, and long-term storage of biological and biochemical materials at ultra-low temperatures. The term is used largely interchangeably with "cryogenic vial," although "cryogenic tube" is sometimes applied to larger-format or specialized geometries, including straws and tubes used in reproductive cryobiology. Cryogenic tubes hold cells, tissues, serum, plasma, nucleic acids, proteins, microorganisms, and diagnostic specimens at temperatures typically below −80°C and down to −196°C in the vapor phase of liquid nitrogen. Their performance depends on an integrated design of tube body, closure, sealing gasket, and, in advanced formats, permanent identification features that support traceability across extended storage periods.

Material Composition and Temperature Performance

The tube body is manufactured predominantly from polypropylene, selected for its chemical resistance, mechanical toughness, and dimensional stability across repeated freeze–thaw cycles. Medical-grade virgin polypropylene conforming to USP Class VI standards is commonly specified to ensure biocompatibility for direct contact with biological materials. The polymer must remain sufficiently rigid to hold shape under pressure yet sufficiently compliant to permit effective gasket compression at the cap–tube interface.

Cryogenic tubes typically exhibit a working temperature range from approximately −196°C to +121°C, covering vapor-phase liquid nitrogen storage and autoclave sterilization. This range does not imply suitability for direct immersion in liquid-phase nitrogen.