In v5.0, OpenSpecimen allows you to attach custom fields at distribution protocol (DP), DP requirements and order level. This allows you to collect DP specific data that is not currently captured in OpenSpecimen.
E.g. MTA document with each DP, address of the requester, external request ID, etc.
This can be configured at the system level or specific DP level. For more details, refer to the wiki page.
Thanks,
Shraddha