What Is a Cryovial? Types & Uses

Last verified: October 6, 2026. A cryovial is a small, screw-capped tube designed to hold biological or chemical samples at extremely low temperatures. The name combines “cryo,” from the Greek for cold, with “vial.” Cryovials are made of plastic that stays intact, rather than turning brittle and cracking, in ultra-low-temperature freezers and in the cold of liquid-nitrogen storage, and they are fitted with caps and seals intended to keep the contents secure and uncontaminated through freezing and thawing.

The problem a cryovial solves is long-term preservation. Living cells, tissue fragments, microbial stocks, and many biological reagents degrade quickly at ordinary temperatures. Cooling them to extremely low temperatures slows or effectively halts the chemical and biological activity that causes that degradation, so a sample can be stored for a long time and recovered when it is needed. An ordinary laboratory tube is not built for this. Plastics that are perfectly adequate at the bench can crack or split when chilled to these temperatures, and a cap that seals well at room temperature may loosen as materials contract. A cryovial is engineered specifically for that stress.

This page is general educational information, not clinical, laboratory, or safety training. Always follow your institution’s procedures, the vial manufacturer’s instructions, and your facility’s cryogenic safety rules.

What a Cryovial Looks Like and How It Is Built

Most cryovials are small cylindrical tubes, typically holding on the order of a milliliter or a few milliliters, though larger sizes exist. They are usually molded from polypropylene, a plastic that tolerates cold and resists chemicals well. Several features distinguish them from a general-purpose microtube:

Screw caps with sealing features. A secure closure matters a great deal, because a poor seal can let contaminants in or let sample out. Many caps include an internal gasket or o-ring. Whether a vial is intended for use in liquid nitrogen itself, or only in the vapor above it, is a specification to read carefully.
Internal or external threads. Some vials have the thread on the inside of the cap and some on the outside. The distinction matters in practice: designs differ in how well they keep the sample sterile when the cap is opened and in how they behave in liquid-phase storage. Manufacturers describe the intended use of each style.
A marking area and graduations. A frosted or printed writing area, and often a barcode area, lets users record sample identity. Labels and inks must also survive extreme cold, which is a real practical problem in sample storage.
A conical or round bottom. Some have a self-standing base for use on a bench or rack, and others have a rounded or conical base for placement in storage boxes.
Color-coded caps or inserts. These help staff organize samples visually in a crowded freezer box.
Sterility. Cryovials are commonly sold sterile, since many contain living cells that will later be cultured.

Who Uses Cryovials, and Why

Cryovials are standard equipment across the life sciences and in clinical and biobanking settings. Typical uses include:

Cell line banking. Cultured cells are frozen in a protective medium and stored so that a stock of known origin can be revived later. This keeps research reproducible and avoids having to keep every line growing continuously.
Microbial stocks. Bacteria, yeast, and other microorganisms are preserved so a strain can be recovered years later without drift from continuous culturing.
Tissue and biospecimen storage. Biobanks and clinical research programs store samples for future analysis. Here, record-keeping, consent, and traceability matter as much as the vial.
Stem cell and primary cell storage. Valuable, hard-to-replace cells are preserved in aliquots.
Reagent and aliquot storage. Enzymes, antibodies, nucleic acids, and other sensitive reagents are divided into small portions and frozen so that each portion is thawed only once.

Before cells are frozen, they are usually grown in culture, sometimes at scale in a bioreactor, and often counted and checked for viability with a tool such as a hemocytometer so that each vial receives a known, consistent amount.

Types of Cryovials

Cryovials vary in a few ways that matter when choosing among them:

Internal-thread cryovials have threads on the inside of the cap. They are often chosen for cleaner handling and for storage conditions where the vial is kept in the vapor phase.
External-thread cryovials have threads on the outside of the neck. They are common and often easier to handle with gloves, and manufacturers specify the storage conditions they are made for.
Vials with barcoded or 2D-coded bases and caps support automated tracking and inventory systems, which are valuable in large collections.
Vials with specialty caps include those with tamper-evident seals, color-coded tops, or sealing gaskets designed for particular storage methods.
Different volume sizes let users pick a vial matched to the aliquot size, which reduces waste and avoids partly filled vials.

The right choice depends on the sample, the storage method, the tracking system in use, and the facility’s safety rules. Suppliers publish what each vial is rated for, and those ratings should be treated as part of the purchase specification.

How a Cryovial Differs From Adjacent Equipment

Microcentrifuge tube. A standard microcentrifuge tube is designed for bench use and spinning, not for storage at ultra-low temperatures. Some labs freeze samples in them for short periods at ordinary freezer temperatures, but they are not engineered for extreme cold or for long-term cryogenic storage.
Conical centrifuge tube. A conical tube is a larger, general-purpose container. It is meant for spinning and holding larger volumes, not for cryogenic storage.
Ordinary glass vial. Glass vials can crack under thermal stress, which is one reason plastic cryovials are common for cryogenic work.
Cryogenic storage straws and bags. These are alternative formats for particular applications such as reproductive biology or large-volume cell products; cryovials are the usual format for routine research cell banking.
The storage system. The vial is the container; the freezer or liquid-nitrogen tank is the storage equipment. Different tools do different jobs, and a vial rated for one storage method is not automatically suitable for another.

How the Freezing Process Fits In

Cells are rarely dropped straight into extreme cold. In general terms, living cells are suspended in a medium containing a cryoprotectant, a substance that reduces damage from ice crystals forming inside cells, and then cooled in a controlled way before being moved to long-term storage. The details of that process, including the cooling rate and the thawing steps, are protocol-specific and belong in a validated procedure from your institution or supplier rather than in a general explanation. Cryovials are the container that carries the sample through each stage of that workflow.

Practical Notes for Research-Administration, Procurement, and Lab-Management Readers

Cryovials are a small line item, but they sit at the center of a large and valuable asset: the sample collection. The practical issues are more about management than about the tube itself.

Safety. Ultra-low-temperature and liquid-nitrogen work carries real hazards, including cold burns, asphyxiation risk in poorly ventilated spaces, and the risk that a vial stored in liquid can take on liquid nitrogen and then rupture as it warms. Institutions set their own training, personal protective equipment, and handling rules. Staff should be trained under those rules before handling cryogenic storage.
Match the vial to the storage method. A vial that is suitable for an ultra-low-temperature freezer or vapor-phase storage may not be appropriate for immersion in liquid nitrogen. Specifications decide this, not appearance.
Inventory and traceability. A frozen sample that cannot be located or identified has little value. Barcoded vials, an inventory system, and clear labeling practices protect the investment. Labels that fall off in the cold are a common failure and a good reason to specify cryo-rated labels.
Power, backup, and monitoring. Freezers and tanks depend on power or liquid-nitrogen supply, so alarms, monitoring, and backup plans protect the samples stored in them. A single equipment failure can mean the loss of years of work.
Consent, ownership, and regulation. When vials hold human-derived material, questions about consent, data protection, ethics review, and transfer agreements apply. Those obligations follow the samples, and research administrators are often involved in them.
Cost and consistency. Changing vial brands midstream can introduce variability in performance or fit within existing racks and boxes. Standardizing on a vial type, and checking that it fits the storage system, avoids surprises.

For broader context on pricing and sourcing choices for laboratory consumables and instruments, see CASRAI’s other equipment guides, such as what a pipette is, which covers the tool commonly used to fill vials with a precise amount of sample.

The Short Version

A cryovial is a small, sealed, cold-tolerant tube made for storing samples such as cells, microbial stocks, tissue, and sensitive reagents at ultra-low temperatures. It differs from an ordinary tube in its materials and its closure, which are designed to survive extreme cold without cracking or leaking. The details that matter are the thread style, the storage method the vial is rated for, labeling and tracking, and the safety rules that govern cryogenic work.

Frequently Asked Questions

What is a cryovial used for?

It is used to store samples such as cultured cells, microbial strains, tissue, and reagents at very low temperatures so they can be preserved for long periods and recovered later.

Can I use a regular microcentrifuge tube instead of a cryovial?

For short-term storage at ordinary freezer temperatures, some labs do. For ultra-low-temperature or liquid-nitrogen storage, a purpose-built cryovial is the appropriate choice, because ordinary tubes are not designed for those conditions and may crack or leak.

What is the difference between internal-thread and external-thread cryovials?

The difference is where the threads sit on the cap and vial. Each style has handling and storage trade-offs, and manufacturers state which storage conditions each is designed for, so check the product documentation.

Are cryovials sterile?

Many are sold sterile because they commonly hold living cells that will later be cultured. The product labeling will state whether a given pack is sterile.

Can cryovials be reused?

They are generally sold as single-use consumables. Reuse raises contamination and integrity concerns, and many institutions do not permit it, so follow your facility’s policy and the manufacturer’s guidance.

Why does a cryovial have to be filled to a limited level?

Liquids expand as they freeze, so manufacturers typically recommend leaving some headspace and not filling to the brim. The exact fill guidance is given in the product instructions.