The choice between vapour phase and liquid phase liquid nitrogen storage has real clinical implications for UK IVF laboratories – and it deserves a clear, honest answer rather than a generic features comparison.
Liquid Phase Storage
In liquid phase storage, samples are immersed directly in liquid nitrogen at -195.8°C. The temperature is consistent and the cooling is immediate. The concern – and it is significant in a licensed UK clinical setting – is the theoretical risk of cross-contamination between samples sharing the same liquid nitrogen bath. HFEA guidance acknowledges this, and some UK clinics with patients storing samples with transmissible infections have moved away from liquid phase for that patient group.
Vapour Phase Storage
Vapour phase storage keeps samples in the nitrogen vapour above the liquid, typically at temperatures between -150°C and -190°C. Samples are never in contact with the liquid nitrogen itself, eliminating the cross-contamination pathway entirely. The trade-off is temperature uniformity – vapour phase vessels can have a gradient between the bottom and top of the storage space, though well-designed modern vessels manage this effectively.
What UK IVF Labs Currently Use
Most UK IVF laboratories use liquid phase storage for the majority of their samples, with vapour phase vessels used specifically for samples from patients with known transmissible infections. The CBS High Security Vitrification Kits use sealed carrier devices specifically designed to minimise cross-contamination risk in liquid phase storage, giving clinics a practical middle ground. For specific vessel advice, speak to the Cryolab team or explore our full storage vessel range.
