Concerning transport, the WHO classifies class 6.2 infectious materials in three categories:

1. Category A

2. Category B

3. Exempt human or animal sample

Category B was created by the ADR in their 2003 edition, in order to standardize and economise on shipments without failing to comply with the regulations; almost all the substances that are shipped are included here. This change is due to the fact that grouping all substances in category A, meant a huge logistic effort, little in keeping with the risk of infection of some of the materials.

Most of the samples shipped do not pose such a high risk as those included in Category A. However, just as with any blood drawn during a normal hospital day, the protocol is that appropriate for a contaminated sample (single-use sterilised materials that will be destroyed afterwards); Category B has a series of measures which significantly limits the risk of an infection, and are compatible with the daily work and the budgetary limits of the bodies that manage them. In this way, the existing risk can be addressed through relatively modest means.