Dry ice sublimates directly from solid to gas, which keeps the inside of a shipping container cold without the meltwater issue that comes with regular ice. Validated containers for this purpose are designed and tested to hold a target temperature range for a defined duration, accounting for a given quantity of dry ice and expected transit time for an overnight shipment.
Because dry ice sublimates continuously, the amount of refrigerant available declines over the course of transit. A shipment delayed beyond its planned transit window, held in a warm environment, or opened and resealed improperly can run out of cooling capacity before the product reaches the clinic, even if the container was packed correctly at the start.
Clinics receiving a dry-ice shipment should open it promptly, check for remaining dry ice and any temperature indicator included in the package, and record the condition of the shipment on arrival. Carbon dioxide gas can also build up in an enclosed space during sublimation, so containers should be opened and handled with normal ventilation precautions rather than treated as routine parcel freight.
Dry ice shipments have a finite cooling window, so clinics should plan for prompt receipt and document the condition on arrival rather than letting a package sit before checking it.