Sample-level metadata?

[nickp60]

Hello! I am excited to try working with MITRE. Looking through the examples it looks like the metadata is given at the subject level, with the only metadata at the sample level being the time and subject id. Is there a way to include sample-level metadata? I want to be able to incorporate drug exposures, where we have some samples collected pre- and some post- exposure. Summarizing the exposure at the subject level discards that info. Any input would be appreciated!