Cryo Vial-Internal Thread

Quick Answer: The Cryo Vial-Internal Thread is a small plastic storage vial for ultra-low temperature work, in which the cap screws down inside the vial’s mouth. An internal thread cryovial is used to freeze and store cell lines, microbial stocks, sera and tissue samples at −80 °C or in liquid nitrogen vapour, with the sample kept sealed until it is thawed.

Internal Versus External Thread

Cryovials are made with two thread designs. On an internal thread cryovial the cap has a threaded plug that screws into the vial, so the outer diameter stays the same from base to cap and vials pack closely in a box grid. On external thread vials the cap screws over the outside of the neck. Because the internal design puts the cap’s plug into the vial opening, the sample must be kept clear of the thread when filling; external threads are sometimes preferred where contact between cap and sample is a contamination concern.

Cryovials are usually polypropylene, and many designs seal the cap against the vial with a silicone washer or O-ring. A white writing area and printed graduations are common, and a star-shaped or skirted foot lets many vials stand on their own and lock into racks. Volume, sterility, seal type and graduations for this listing are not given in the title.

Safe cryogenic storage depends on fill level and storage phase. Vials should not be filled above their stated working volume, leaving room for the contents to expand as they freeze. Storage in the vapour phase above liquid nitrogen is generally preferred to submerging vials, because liquid nitrogen can seep into a submerged vial and then expand violently when it warms. For a screw-cap vial meant for ordinary storage, see the Storage Vial With O-Ring.

Applications

• Freezing cell lines in freezing medium for long-term banking
• Storing bacterial and yeast glycerol stocks at −80 °C
• Aliquoting serum, plasma and antibodies to avoid repeated freeze-thaw cycles
• Keeping tissue and biopsy samples for later molecular analysis

Filling, Freezing and Thawing

• Fill below the working volume mark, and keep liquid off the threads
• Label with cryo-grade labels or markers before freezing
• Store in the vapour phase, or use a protective sleeve if liquid-phase storage cannot be avoided
• Wear a face shield when taking vials out of liquid nitrogen, and thaw them in a closed container or behind a screen

Specifications

Why Choose LabEquip

Cryovials of this design are a staple order for cell culture labs, microbiology departments, biobanks and hospital research units. LabEquip supplies them with Cryo Coders and cryo boxes in Biology Lab Products; ask about volume and sterility through our contact page.

Frequently Asked Questions

What is the difference between internal and external thread cryovials?

Internal thread vials have a cap plug that screws into the vial, keeping a slim, even outer diameter that packs well in boxes. External thread vials have the cap over the outside of the neck, which keeps the cap plug out of the sample opening.

How full can a cryovial be filled?

Fill only to the stated working volume, which is well below the brim. The contents expand on freezing, and overfilled vials can leak or crack.

Can cryovials be stored in liquid nitrogen?

Vapour-phase storage above the liquid is generally recommended. If vials are submerged, liquid nitrogen can enter through the seal and expand rapidly when the vial is warmed, which can make it burst.

Why are cryovials thawed quickly?

Cells generally recover better from rapid thawing, typically in a 37 °C water bath with gentle agitation until only a small ice crystal remains. Slow thawing gives damaging ice crystals time to grow inside the cells.

Can cryovials be autoclaved and reused?

Polypropylene vials can generally withstand autoclaving, but cryovials are normally used once, since seals and labels may not hold after sterilisation. Many are supplied sterile for single use.

What labels work on cryovials?

Use labels or markers rated for cryogenic temperatures and apply them to dry vials at room temperature. Ordinary labels can peel off in the cold, and ordinary inks may fade with solvent disinfectants.

Last Updated: September 2026