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Category A Infectious Substances

Infectious substances are now divided into two categories described below that are based on a detailed, case-by-case, risk assessment of microorganisms known to be pathogens. The categorization is the result of the consideration of scientific data concerning the risks of transmission and infection posed during transport of each species of microorganism.

Category A - an infectious substance that is transported in a form that, when exposure to it occurs, is capable of causing permanent disability, life-threatening or fatal disease to humans or animals. An exposure occurs when an infectious substance is released outside of the protective packaging, resulting in physical contact with humans or animals.

1. Infectious substances meeting these criteria which cause disease in humans or both in humans and animals must be assigned to UN 2814. Infectious substances which cause disease only in animals must be assigned to UN 2900.
   
   
2. Assignment to UN 2814 or UN 2900 must be based on the known medical history and symptoms of the source human or animal, endemic local conditions, or professional judgment concerning individual circumstances of the source human or animal.

Category B - an infectious substance that does not meet the criteria for inclusion in Category A. Infectious substances in Category B must be assigned to UN3373 except for cultures which must be assigned to UN 2814 or UN 2900 as appropriate.

Cultures – laboratory stocks are the result of a process by which pathogens are amplified or propagated in order to generate high concentrations, thereby increasing the risk of infection when exposure to them occurs. This definition refers to cultures prepared for the intentional generation of pathogens and does not include cultures intended for diagnostic and clinical purposes (unless included in the Category A)