Saf-T-Pak Shipping Course Practice Test

The mail system under the Universal Postal Union does not allow highly dangerous infectious materials to be sent through regular international post. Category A Infectious Substances are capable of causing life-threatening disease in healthy individuals and require strict containment, handling, and emergency procedures that standard postal services cannot provide. Because of that elevated risk, they are not permitted to be mailed.

In contrast, Category B Infectious Substances can be mailed if they are properly packaged and labeled according to the guidelines, Exempt patient specimens may be shipped under exemption criteria, and dry ice can be sent as a cooling agent when packaged to meet safety requirements. Those conditions make them eligible for mail under the right regulations, whereas Category A is not.