Temperature and the cold chain
Aim for 2 to 8°C once reconstituted. Brief warmth on the way home from the shop is survivable; hours in a hot car or a sunny windowsill is not. Freezing is worse than heat because it is instant and irreversible.
The range and what sits outside it
| Temperature | What it is | Verdict |
|---|---|---|
| Below 0°C | Freezer, fridge back wall | Never. Ice crystals cause damage. |
| 2–8°C | Fridge, middle shelf | The target once reconstituted. |
| 8–25°C | Room temperature | Brief periods only, in transit. |
| Above 25°C | Hot car, windowsill, radiator | Avoid. Heat is cumulative. |
Heat is cumulative, cold is a cliff
Warmth degrades things gradually, so twenty minutes at room temperature is a small deduction from a large budget. That is why taking a vial out to warm up before injecting is fine.
Freezing is not gradual. Ice forms, crystals do mechanical damage, and thawing does not reverse it. This is why the freezer is a hard no while the counter for ten minutes is not.
The cold chain in practice
- Coming home: straight into the fridge, do not leave it in the car
- Day out: the travel case with its ice pack, frozen overnight
- Flying: hand luggage with an ice pack, never the hold
- Power cut: a closed fridge holds temperature for hours, so keep the door shut
- Heatwave: check the fridge is actually holding 2 to 8°C, because many run warm when the kitchen is hot
Aircraft holds regularly drop below freezing. That single fact is the reason anything temperature-sensitive goes in the cabin, not the suitcase.
Warming before injection
Fifteen minutes on the counter is enough and makes a real difference to comfort. Do not use warm water, a radiator or your hands wrapped around it: sudden heat is exactly the thing you have been avoiding.
Questions
- How long can it sit at room temperature?
- For warming before an injection, fifteen to thirty minutes is routine. For longer periods, follow the supplier's guidance for the specific compound.
- Is a fridge thermometer worth it?
- For a few pounds, yes. Domestic fridges vary by several degrees between shelves and most people have no idea what theirs actually runs at.