A dry shipper contains an internal sorbent matrix — typically a zeolite-based material — that absorbs liquid nitrogen before transport. During transit, no free liquid nitrogen is present. The matrix releases nitrogen vapour slowly, maintaining cryogenic temperatures between approximately -150°C and -190°C throughout the journey. A standard liquid nitrogen dewar holds free liquid nitrogen, which creates spillage risk during transport and subjects the vessel to dangerous goods restrictions for air freight.
The practical consequences of this difference are significant for IVF clinics running inter-clinic sample transfers. A correctly charged dry shipper is accepted for air freight as not restricted under IATA Special Provision A152, with no dangerous goods declaration required for the nitrogen itself, which removes a substantial administrative and logistical burden. Standard dewars require specialist courier handling and dangerous goods paperwork that most clinical courier services are not equipped to provide.
Both vessel types maintain the critical biological threshold of approximately -130°C below which cryopreserved samples enter the glassy state and biological activity stops. For clinical embryo and sperm transport, the CryoStork range from Cryolab covers three models — the V2 for compact single-patient transfers, the V3 for routine inter-clinic transfers, and the V10 for high-volume or extended-distance movements. Contact Cryolab to discuss which model suits your transfer pattern.
