Detecting the exposure to (an agent)

The difference between detecting exposure and detecting presence affects IVDR classification. A test for antibodies shows that a person met the agent, not that it is present now.

means the indirect detection of an agent (present or past exposure). - by detecting the presence of surrogate markers, such as antibodies against components of the agent.

MDCG 2020-16 Rev.5, Section 2, Definitions