The component inside sets the carrier's temperature; the guide describes three regimes:
| Component | Transport temperature | Time and caution |
|---|---|---|
| Red cells | +2 to +6 °C; 1-10 °C on delivery | Journey of up to 24 hours |
| Platelets | 20-24 °C, never chilled | Transport without agitation no longer than 24 hours |
| Fresh frozen plasma | Frozen, close to storage temperature | Frozen bags can crack |
The guide requires cooling packs not to be in close contact with the bags; red cells have a lower limit of 1 °C, so a bag resting on a frozen plate is damaged. A carrier therefore has a permanent separating layer and an indicator that monitors transport temperature. When red cells and platelets travel in the same vehicle, their ranges do not overlap, so they go in two separate containers.
On delivery, temperature is read with a thermometer placed between two bags after five minutes, or with an electronic device that measures at the bag surface. Dispatch and delivery readings are recorded; the blood service unit decides, under its current procedure, what happens to a component that arrives out of range.
