Sending UN3373 samples: P650 packaging, marking and what goes with them
UN3373, Biological Substance, Category B, is Class 6.2 material that is infectious but does not meet the Category A criteria, such as most diagnostic patient specimens. By road it travels under ADR packing instruction P650: a leak-proof primary receptacle, leak-proof secondary packaging and a rigid outer, with absorbent for liquids, an itemised list of contents, and the UN3373 diamond mark next to the words "BIOLOGICAL SUBSTANCE, CATEGORY B".
Category A, Category B and exempt specimens
Infectious substances are split into two categories. Category A (UN2814 and UN2900) covers material capable of causing permanent disability or life-threatening disease in otherwise healthy people or animals on exposure. Category B is infectious material that does not meet that test, and is assigned UN3373. Classifying the sample is the consignor's job and normally rests with the clinician or laboratory.
Some specimens, where there is minimal likelihood that pathogens are present, can be sent as "Exempt human specimen" or "Exempt animal specimen" in suitable packaging, outside UN3373. If you are unsure, ask your laboratory or your Dangerous Goods Safety Adviser rather than your courier.
P650 triple packaging
The packaging has three parts, and all three are required:
- A leak-proof primary receptacle (the sample tube, pot or vial). For solids it must be sift-proof.
- A leak-proof secondary packaging that encloses the primary receptacle. Several primaries may go in one secondary if they are wrapped or separated so they cannot touch.
- A rigid outer packaging. At least one surface must be at least 100 mm by 100 mm, so there is room for the mark.
- For liquids, enough absorbent material between the primary and the secondary to soak up the entire contents.
- The completed package must pass a 1.2 m drop test.
Marking
The outer packaging carries the UN3373 mark: a square set on its point, each side at least 50 mm, with a line at least 2 mm wide and the letters "UN3373" at least 6 mm high. Next to it go the words "BIOLOGICAL SUBSTANCE, CATEGORY B", also at least 6 mm high. If an overpack is used, it is marked with the word "OVERPACK" and the same marks, unless they are visible through it.
No Class 6.2 hazard label is required for Category B. That label, and the much heavier packaging regime, belong to Category A.
Temperature
Where samples need to stay cool or frozen, the coolant goes outside the secondary packaging, with the secondary held in place so it cannot move when the coolant melts or sublimes. If wet ice is used, the outer packaging or overpack must be leak-proof.
Dry ice (UN1845, solid carbon dioxide) must never go in a sealed container, because it gives off gas. The packaging must let the carbon dioxide escape, and the package is marked to show that dry ice is being used as a coolant. In a closed van the gas builds up, so our driver needs to know it is on board.
We carry samples in a dedicated van at ambient temperature, straight from collection to delivery. We do not provide temperature-controlled vehicles or temperature monitoring of our own, so the packaging has to hold the temperature for the journey. Tell us how long that is and we will give you an honest journey time.
What goes with the package
An itemised list of contents goes between the secondary packaging and the outer packaging. When packed and marked to P650, UN3373 is not subject to the other requirements of ADR, so no ADR transport document is needed by road and no placards or ADR-certificated driver are involved. Most laboratories still send a manifest or chain-of-custody sheet, and we sign for the package at each hand-over.
Please also give us the collection and delivery contacts, the required delivery time, and whether dry ice is in the box.
This page explains the framework; it is not a compliance opinion on your consignment. Send us the UN number, the packing group and the weight or volume per package and we will tell you in writing which route it travels under.
What X-Eagle will carry
ADR-trained driver available. Full ADR loads are accepted subject to class and quantity, confirmed before booking; small-quantity / Limited Quantity loads handled routinely. Send us the UN number, class, packing group and quantity and we will tell you in writing whether we can take it before you book — if a load is outside what we can carry, we say so on the first call.
What we will not carry
- Category A infectious substances (UN2814, UN2900).
- Samples not packed to P650 or not marked UN3373.
- Placarded (full ADR) loads as a routine service: we quote them only case by case, with the class and quantity confirmed before booking.
- Class 1 explosives and Class 7 radioactive material.
Common questions
What is UN3373?
UN3373 is Biological Substance, Category B: infectious material in Class 6.2 that does not meet the criteria for Category A. Most diagnostic patient specimens sent to a laboratory fall under it.
What is P650 packaging?
P650 is the ADR packing instruction for UN3373. It requires a leak-proof primary receptacle, leak-proof secondary packaging and a rigid outer packaging, absorbent for liquids, an itemised list of contents between the secondary and outer, and a package able to pass a 1.2 m drop test.
Does a courier need an ADR certificate to carry UN3373?
No. UN3373 packed and marked in accordance with P650 is not subject to the other requirements of ADR for road transport, so no ADR vocational certificate or placarded vehicle is needed.
Can you carry Category A infectious substances?
No. Category A (UN2814 and UN2900) has a much stricter regime and we do not carry it.
Can samples travel with dry ice?
Yes, if the packaging lets the carbon dioxide escape and the package is marked to show dry ice is used as a coolant. Tell us before collection so the driver knows it is on board.
Send us the UN number and we will tell you how it travels
The UN number, the packing group and the quantity per package settle it in one call. We will put the answer in writing before anything is collected.