Transportation of infectious substances

This part of the site provides an overview of the transport requirements for materials containing, or contaminated with, blood-borne viruses.

In the context of this guidance, the most likely materials presenting a risk of infection from blood-borne viruses, which will be subject to transport include:

  • patient specimens/samples;
  • cultures of blood borne viruses; and
  • waste from spillage/treatment of workers.


Biological agents, or materials that contain or may contain them, are allocated to UN Division 6.2 - infectious substances. Division 6.2 includes biological products, cultures, specimens, genetically modified microorganisms (GMMs), genetically modified organisms (GMOs) and medical/clinical waste.

There are 4 steps involved in the safe transport of infectious material. These are:

  • Classification;
  • Packaging;
  • Labelling; and
  • Transporting.


The transportation of infectious substances is divided into the following categories:

  • Category A: an infectious substance which is carried in a form that, when exposure to it occurs, is capable of causing permanent disability, life threatening or fatal disease in otherwise healthy humans or animals. This definition is supplemented by an indicative list of pathogens, which include HIV and hepatitis B viruses (but not hepatitis C virus), when in the form of cultures but does not encompass specimens from patients suspected of having these infections.
  • Category B: any infectious substance that does not meet the criteria for inclusion in category A. These are assigned to UN 3373. This would include specimens from patients with known or suspected HIV, HBV or HCV infections.

Samples of materials such as blood, tissue, excreta, secreta, etc collected from humans or animals are considered, as a minimum, category B infectious substances. Clinical or medical waste that contains category B infectious substances (with the exception of cultures), or that only has a low probability of containing infectious substances, is assigned to UN 3291.


Transport of infectious substances requires a basic triple packaging system. It consists of three layers as follows:

  • Primary receptacle - a primary watertight leak-proof receptacle containing the specimen. The receptacle is packaged with enough absorbent material to absorb all fluid in case of breakage.
  • Secondary packaging - a second durable, watertight, leak-proof packaging to enclose and protect the primary receptacle(s). Several cushioned primary receptacles may be placed in one secondary packaging, but sufficient additional absorbent material shall be used to absorb all fluid in case of breakage.
  • Outer packaging - secondary packaging is placed in outer shipping packaging with suitable cushioning material. Outer packaging protects contents from outside influences, such as physical damage, while in transit.

Each completed package is normally required to be marked, labelled and accompanied with appropriate shipping documents (as applicable). Specific details on the packaging requirements and specifications are available from the Department for Transport.


Packages containing infectious substances should be marked with:

  • the proper shipping name, eg 'Infectious substance, affecting humans';
  • the appropriate UN number (eg for 'Infectious substances, affecting humans' this would be UN 2814); and
  • the appropriate warning label.


In general, category B samples that are sent using UN 3373 can normally be sent via the postal service. However, as a proportion of the post in the UK will travel by air at some point in its journey, the packaging will need to comply with the ICAO standards. Similarly, some courier companies will accept only category B infectious samples, hence it may be necessary to use a different company for category A infectious samples. You should always discuss your transport requirements with your chosen carrier.

Further information

The Department for Transport sets out the legal requirements and provides specific detailed guidance on the classification, packaging, labelling and transport of infectious substances, in their publication Transport of Infectious Substances.

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Updated 2022-05-13