Using 'unspecified' system LOINCs

We are in the process of setting up a lab feed to a common data warehouse. We now have LOINCs in place in our lab system. We will be sending historical lab records, which do not have LOINC codes. A crosswalk file is required in which the “analyte (OBX 3.1) to LOINC (OBX 3.4)” relationship needs to be one-to-one. In our lab application we use the same analyte(component) with different specimens (systems) and thus coded system specific LOINCs. For this crosswalk file, I am thinking I will need to remove the system specific codes and substitute in a LOINC that references an ‘unspecified’ system. I have found some LOINCs that are appropriate. Others I am only finding that there is a ‘component/unspecified system’ pairing with sCnc property, but not a corresponding mCnc. The mCnc property with unspecified system is the majority of what I am looking for. Glucose and Creat are two examples. I have approximately 24. I am looking for any suggestions or thoughts on this. Could these LOINCs be requested? are unspecified system LOINCs not recommended?

I personally would recommend submitting the 24 unspecified systems for MCNC scenarios through RELMA. It’s through the stewardship of the adopters and implementers that the different architectures of lab reporting systems are sent on to Regenstrief for consideration. It hasn’t been my experience that Regenstrief will post acceptance from email, verbal or Forum communication without a detailed submission. There are guidelines in the RELMA manual on how to create the submission. Feel free to ping me on the process if you have any questions.