What to Do When a Cold-Chain Order Arrives

Open it immediately

A cold-chain package is designed to hold temperature for a defined transit window, not indefinitely. Left on a doorstep or in a hallway it continues warming from the moment that window closes. Opening and refrigerating promptly is the single highest-value thing a recipient does.

Inspect before you store

Check the cold pack: still cold and intact, or thawed and warm. Check the product itself. A lyophilised cake should be intact and uniform. A collapsed, melted or discoloured cake indicates a temperature excursion. Pens should be clear and free of particulates. Photograph anything that looks wrong before you handle it further - evidence is much easier to gather now than later.

Refrigerate, never freeze

Two to eight degrees Celsius is the target for essentially everything in this category. Freezing is damaging to peptides and proteins: growth hormone and the gonadotropins are folded proteins that lose activity when frozen, and repeated freeze-thaw is particularly destructive to LL-37 and IGF-1. A domestic freezer is not a safer version of a fridge.

Mind where in the fridge

The door is the warmest part of a refrigerator and swings in temperature every time it opens. The back of a middle shelf is the most stable position. Avoid the very back of the bottom shelf in some models, where contact with the cooling plate can freeze items.

Record the date you reconstitute

Once reconstituted, the in-use window is finite and considerably shorter than the lyophilised shelf life. Writing the date on the vial takes seconds and is the only reliable way to know later. The batch documentation states the window; assumptions about it are usually optimistic.

Raise problems immediately

Temperature excursions are resolvable when reported on arrival with photographs. They are much harder to resolve weeks later, because by then no one can distinguish a transit problem from a storage one.