Infectious substances are substances known to contain, or can reasonably be expected to contain viable microorganisms, including bacteria, viruses, rickettsiae, parasites, or fungi, or other agents such as prions, that can cause disease in humans or animals. Cultures or lab stocks (e.g., tissue culture systems and agar plates) in which such pathogens are amplified or propagated in high concentrations are also considered an infectious substance.
Infectious substances are further categorized as Category A and Category B infectious substances.
- Category A infectious substances are cultures of microorganisms listed in Appendix A where the word “culture only” follows the name of the organism, or materials (such as tissue or blood, in addition to cultures) that contain or can reasonably be expected to contain organisms listed in Appendix A.
- Category B infectious substances are those that do not meet the criteria for inclusion as a Category A substance. Category B substances should be labeled as “Biological substance, Category B.”
- A culture plate or slant shipped for diagnosis or clinical purposes is considered a “Biological substance, Category B” unless it is a culture of a highly pathogenic organism or is included in Appendix A. However, if the organism is followed by the words “culture only” in Appendix A, a patient specimen (blood, tissue, etc.) suspected to contain that particular organism must be shipped as a “Biological substance, Category B.” For example, a blood or tissue sample from a patient with rabies or HIV would be shipped as a “Biological substance, Category B” since Appendix A lists “culture only” after the name of each of these viruses.