The temperature band comes from the test, not from the courier. Many routine chemistry, haematology and microbiology specimens travel at 2–8 °C, some are valid at room temperature, and a much smaller set goes frozen — so the transport decision starts with the receiving lab's requirement for that specimen. The packaging job is to hold that band while the outside of the box still satisfies UN3373 Category B expectations.
Temperature and packaging are usually treated as two separate topics. In practice they meet at the gel pack, which changes the weight, the condensate and the labelling inside a package that still has to pass the same pressure and drop expectations.
Which Temperature Band Does Each Specimen Need?
Confirm every entry against your own lab's collection manual before printing a chart, because labs differ on details and a courier route is not a clinical decision. The pattern below is the common one.
| Temperature band | Specimens that typically travel this way | Packaging points |
|---|---|---|
| 2–8 °C refrigerated | Most routine chemistry, haematology and coagulation specimens; microbiology transport media per lab instruction | Absorbent sized for the primary volume plus condensate; conditioned gel packs kept off the tube; moisture-resistant labels |
| Room temperature | Specimens whose analytes are reported as affected by chilling, plus many swab and transport-media submissions | Keep out of direct sun and off heated surfaces; no ice; the same three-layer PI 650 structure |
| Frozen | Only the small set of tests your lab requires frozen | Dry ice is itself a regulated dangerous good with its own marking and venting rules; use it only when the lab asks |
| Do not chill | Analytes your lab reports as refrigeration-sensitive | Transport at ambient with the time on the log rather than cold by default |
What Changes in the Packaging When You Add Refrigeration?
Three things. Condensation: a cold primary receptacle inside a warmer box produces moisture, and the absorbent layer has to take the specimen plus that condensate or the secondary package arrives wet. Contact: a fully frozen gel pack resting against a tube can drive that specimen below its band, which is why packs are conditioned deliberately rather than straight from the freezer. Labelling: wet outer packaging lifts printed labels, so use moisture-resistant labels and keep the UN3373 marking, the proper shipping name and the itemised contents list legible at handover.
Does a Category B Shipment Need a Temperature Record?
The UN3373 packing rules govern the package, not the temperature record; that requirement comes from the test, the receiving lab or your own SOP. Where a record is required, the usual pattern is a min/max thermometer or a data logger travelling with the consignment, placed next to the specimen rather than in a corner of the box, with the sealing time and the receipt time recorded on the transport log. Reading it matters — an excursion you only notice when a result is questioned has already lost most of its value.
How Does a Heat Wave Change the Calculation?
In a Canadian summer, a configuration that holds band in April can drift in July. The variables that matter are how many gel packs you use and how they were conditioned, whether the outer box is insulated, where the box sits in the vehicle — a closed trunk and a dashboard are both worse than a shaded footwell — and how long the handover takes. If a route changes seasonally, re-check the configuration instead of reusing the cold-weather one.
What Happens When the Temperature Goes Out of Band?
Do not discard the specimen as a reflex. Record the excursion with times and readings, tell the receiving lab, and ask for a decision in writing: repeat collection or proceed with a caveat. Treat that decision like any other quality record, because if someone asks months later whether the result was reliable, the answer is the log entry rather than anyone's memory of packing the box.
Bags and temperature control are bought together in practice. The 6×9 inch three-wall specimen transport bags with a document pouch and absorbent pad (100-pack) suit routine refrigerated routes, and sites shipping under the UN3373 marking use the 95 kPa UN3373 bag in the same size. Multi-route labs can price both at the bulk quote desk, and the learning hub carries the specimen transport checklists.
Labs that also run a sterilizer can start with a BI 5-pack trial ($12.99, ships free).
Related reading
For the wider workflow, read specimen cold chain in Canada, then a compliant specimen transport workflow from point-of-care site to central lab and choosing 95 kPa specimen bags: sizes and absorbent pads.
Frequently Asked Questions
Do all specimens need to be refrigerated for transport?
No. The band is set by the test. Many routine chemistry, haematology and microbiology specimens travel at 2–8 °C, while some analytes are reported as affected by chilling and travel at room temperature. Your lab's collection manual is the authority.
Can a frozen gel pack damage a specimen?
It can. A fully frozen pack placed against a primary receptacle can drive that specimen below its required band, which is why many routes use conditioned packs rather than straight-from-freezer ones.
Is temperature monitoring required by UN3373?
The packing instruction governs the package, not the temperature record. A record is required when the test, the receiving lab or your SOP calls for one, in which case the logger travels with the consignment.
What should a transport log record for a chilled shipment?
The sealing time, the temperature control used, the courier and handover time, and the reading on arrival. That set lets you reconstruct an excursion without relying on anyone's memory.
CliniEco Medical is a licensed medical device establishment (MDEL #35334).
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