Packaging guidelines Samples must be sent frozen following UN3373 guidelines (Packaging & Transport Requirements - GOV.UK).Recommended Bio-Freeze system (Bio-Bottle).If a pre-paid return slip is included, we can return Bio-Bottles.Alternatively, samples can be sent on dry ice using:CryoPDP (10L box sufficient for frozen transport)World Courier (another reliable service) This article was published on 2025-03-27