There is a problem growing quietly in IVF laboratories worldwide, and most clinic directors are too busy managing it to talk about it publicly.

The samples keep coming in. Egg freezing volumes have risen sharply, from around 700 patients freezing eggs in 2014 to 5,580 in 2024. Frozen embryo transfer has become the dominant mode of IVF treatment, accounting for 48 percent of all IVF cycles carried out in the UK in 2024, up from 24 percent a decade earlier. Donor programmes are expanding. Oncofertility referrals are increasing. The cumulative effect of all of this is that the liquid nitrogen tanks lining the walls of IVF labs are filling up. Some are already full.

Space constraints are among the most cited frustrations from IVF lab directors, particularly as they try to accommodate increasing volumes of stored biological material. Many labs, short on expansion options, resort to storage practices that introduce risk, placing samples in tanks not covered by warranty or configuring vessels beyond their design intent.

This is not a niche operational problem. It is a patient safety issue, and the solution is not more of the same.

The storage maths that no one does early enough

A standard IVF laboratory dewar holds between 3,000 and 8,000 samples, depending on configuration and inventory system. A growing clinic adding 500 new patients per year, each with an average of five stored embryos, adds 2,500 samples to its inventory annually. At that rate, even a well specified mid-sized dewar is full within two to three years. Once it is full, the options are not good: buy another tank, find floor space that may not exist, move samples off-site, or start managing a storage waiting list.

None of those options serve patients well.

The clinics and biobanks that avoid this problem are the ones that plan for ten years of growth at the point of making the storage infrastructure decision, not three. That decision, increasingly, points towards high-capacity large cryogenic storage tanks.

What the CryoBank Series is

The Cryolab CryoBank Series is a range of large steel cryogenic storage tanks designed for high-volume, long-term biological sample storage in both vapour and liquid phase liquid nitrogen.

The series runs across six models, from 350 litres up to 1,800 litres, holding between 15,600 and 95,000 1.2ml or 2ml vials in a compact footprint. That makes it suited to biobanks, IVF clinics, blood banks, tissue banks, cell banks and research facilities.

To put that in practical terms: a single CryoBank 1800-95 can hold the equivalent sample volume of between twelve and thirty standard IVF laboratory dewars, in a fraction of the combined floor space. For a biobank or a high-volume IVF programme, the infrastructure consolidation that represents is significant.

Vapour phase storage: why it matters more than ever

The shift from liquid phase to vapour phase cryogenic storage is one of the most important trends in clinical sample management over the past decade, and the CryoBank Series is designed to support it from the ground up.

In liquid phase storage, samples are submerged directly in liquid nitrogen at -196C. The temperature is consistent, but the recognised risk is cross-contamination. Liquid nitrogen is not sterile, and any pathogen present in the tank environment, however rare, can in principle transfer between samples stored in the same vessel. This is why closed carrier systems and vapour phase storage have become the subject of sustained attention in the cryopreservation literature and in laboratory risk assessments.

In vapour phase storage, samples are held above the liquid surface in nitrogen vapour. The temperature is slightly higher, typically between -140C and -190C, but remains well below the -130C glass transition threshold at which biological activity resumes. Because samples are not immersed in a shared liquid, the route by which contamination transfers between vessels is substantially reduced.

Every tank in the CryoBank Series is engineered to maintain -196C in liquid phase or -190C in vapour phase, even at the highest point of the internal structure. That last detail matters. In a large tank, temperature stratification, the difference between the bottom and the top of the internal structure, is one of the primary technical challenges. A tank holding -190C at its uppermost storage point in vapour phase mode is providing genuine protection for every sample at every level, not just those closest to the liquid nitrogen surface.

The alarm system: where large tank infrastructure earns its cost

A standard IVF laboratory dewar is monitored by the embryologist who walks past it each morning. This works, more or less, for a small-volume facility with regular staffing. It does not work for a biobank storing 50,000 samples, a large fertility network with out-of-hours operations, or any facility where a silent tank failure could destroy years of stored material before anyone notices.

CryoBank tanks come equipped with an extensive audio and visual alarm system monitoring LN2 level, temperature and power status, with remote alarm capability built in.

Remote alarm integration means that a temperature excursion at 3am on a bank holiday weekend triggers an immediate notification to whoever is on call, before the LN2 level reaches a critical point, before samples are compromised, before the situation becomes irreversible. This is not a premium feature. For any facility storing irreplaceable biological material, it is the minimum acceptable standard.

The tanks also include a defog function for clearer sample access, a practical design decision that reflects genuine operational experience rather than specification sheet engineering.

Ergonomics: the problem nobody writes specifications for

Storage density is only half of the operational equation. The other half is access.

A large cryogenic storage tank that requires an embryologist to reach awkwardly into a cold vessel at an uncomfortable height, with limited visibility and manual equipment, creates both safety risks and sample handling risks. Every unnecessary thermal excursion, every moment a sample spends outside the cryogenic environment while being retrieved, is a moment of potential compromise.

The CryoBank Series features a low liftover height, a two-tier folding step and a wide neck opening, up to 635mm on the 1800-95, for high-throughput sample handling. The ergonomic design improves workflow efficiency, reduces physical strain and improves safety for laboratory personnel.

These are not trivial design features. They reflect an understanding that the person using this equipment will be doing so repeatedly, often under time pressure, in a cold environment, handling samples that cannot be replaced. Design that reduces physical strain and improves access angle reduces error rates. It also reduces the musculoskeletal risk to the embryologist, something occupational health considerations increasingly require clinics to address.

Automated LN2 supply: removing the human variable

Manual top-up of liquid nitrogen in a large storage tank is one of those tasks that is simple in isolation and risky in aggregate. Miss a top-up. Misjudge the level. Forget the delivery was delayed. Each individual failure is understandable. The cumulative effect, over years of operation, is a statistical certainty that at some point LN2 levels will fall further than intended.

The CryoBank Series includes automatic liquid nitrogen fill controlled by multiple solenoid valves, which prevents overflows and ensures controlled LN2 dispensing. An optional vacuum-jacketed transfer hose reduces nitrogen consumption and operational costs, and a backup battery is available as an option.

Automated supply removes the human variable from LN2 management. The tank monitors its own level and triggers refilling when required. The solenoid valve system prevents overfilling. The vacuum-jacketed transfer hose minimises the nitrogen lost to evaporation during filling, a meaningful operational cost saving in a facility consuming large volumes of LN2 annually.

Customisable rack layouts: one infrastructure for multiple sample types

A biobank stores DNA extracts in 1.5ml tubes. An IVF clinic stores embryos in straws on canes in goblets. A stem cell laboratory stores cell lines in 2ml cryovials in boxes on shelves. The storage hardware requirements are different for each application, and a single large tank that cannot accommodate all of them is a tank that forces the facility to maintain multiple separate storage systems.

CryoBank tanks are available with customisable square, round or boxed rack layouts, along with optional inventory racks, to suit the diverse needs of each laboratory or facility.

This flexibility matters for facilities serving multiple research programmes, for biobanks storing diverse sample types, and for IVF clinics that also operate andrology services, donor programmes and oncofertility banking alongside their standard embryo storage. One tank, configured appropriately, can serve all of these functions without compromising on storage density or sample organisation.

The touchscreen interface and data logging

CryoBank tanks are equipped with a user-friendly touchscreen interface that simplifies system monitoring and control, with data logging and real-time system updates built in, making it straightforward to track and manage storage conditions.

For HFEA-licensed facilities, records of storage conditions are part of the evidence base that demonstrates gametes and embryos have been kept under validated, monitored conditions. A system that generates a continuous record of temperature, LN2 level and alarm events automatically, and makes it accessible through a touchscreen interface rather than requiring manual log entries, reduces administrative burden and improves the reliability of that record.

For biobanks working towards ISO 20387 accreditation, the same data logging supports the documented quality management evidence that accreditation requires.

Certification, warranty and long-term confidence

Every CryoBank tank is supplied with UKCA and CE marking, a 5-year vacuum warranty and a 2-year parts warranty.

The five-year vacuum warranty deserves specific attention. The vacuum insulation is the thermal heart of any cryogenic dewar. A vacuum that degrades silently over time leads to increased LN2 consumption, reduced holding times and eventually unacceptable temperature instability. A five-year warranty on the vacuum is a statement of confidence in the manufacturing quality, and significant financial protection for the facility making the investment.

Paul Hague, Director of Cryolab and a 40-year veteran of the cryogenic sector who demonstrated controlled-rate freezer technology to Professor Robert Edwards, the Nobel Prize-winning pioneer of IVF, frames the infrastructure decision plainly: “A liquid nitrogen storage tank is a promise. And in reproductive medicine, that promise has to hold for years, sometimes decades.”

A facility choosing a CryoBank Series tank is choosing infrastructure designed to keep that promise at scale.

Who the CryoBank Series is built for

The CryoBank Series is not a product for every laboratory. A small IVF clinic with a steady patient volume and adequate floor space for standard dewars does not need an 1,800 litre steel tank. But for the facilities that do need it, the scenarios are consistent and recognisable.

A growing IVF network that has outgrown its dewar capacity and is managing a patchwork of standard tanks, some of which are approaching end of life. A biobank that needs to consolidate samples from multiple smaller vessels into a single, monitored, high-capacity system. A research institution storing tens of thousands of cell line vials that requires vapour phase storage, automated LN2 supply and continuous monitoring. A fertility clinic planning a new build or significant expansion and making the infrastructure decision that will define its storage capacity for the next ten to fifteen years.

For all of these, the CryoBank Series represents the infrastructure answer that multiple standard dewars cannot provide.

The storage decision that compounds

Storage decisions in cryogenic programmes are unusual. They are made once and lived with for a decade. The tank purchased today will hold samples that arrive next year, and the year after, and for many years beyond that. Its alarm system will be the first line of defence against a failure that happens, if it happens, at the least convenient possible moment. Its vapour phase capability will determine whether the facility can respond to evolving expectations on cross-contamination risk without replacing its infrastructure.

The facilities that get this decision right do not congratulate themselves on their foresight. They simply do not experience the storage crises that constrained facilities manage instead.

Explore the full CryoBank Series range at Cryolab, and read our complete guides to biobanking, liquid nitrogen tanks, cryopreservation and cryogenic freezers for the full picture of what a robust cryogenic storage programme looks like.

Source for UK treatment figures: HFEA, Fertility treatment 2024: trends and figures.