Orders in LOINC database

I’m confused by the ORDER_OBS column in the LOINC database. I assume this must have a different usage/meaning from the recently released common orders Excel file?

Yes, the common order set is small by design…to highlight the most frequently used terms and help prioritize the mapping effort towards those high impact items.

This field is our best (informed guess) as to whether this LOINC code can be used as an Order code (e.g. in an OBR segment) and Observation code (e.g. in an OBX segment), or Both. Many terms can be used as both, panel terms will Order only, and things like calculations or impressions will typically be Observations (you can’t order them directly).

Thank you, Daniel. So how does it differ from the Common Lab Orders Value Set - Version 1.1, which has many fewer items?

We populate the ORDERS_OBSERVATION field for all lab terms in the database. The Common Lab Orders value set is purposely a short set of codes that account for the vast majority of lab orders in the US. It was derived by both empirical and consensus-based approaches. You should consider it a minimun “starter set” and definitely doesn’t include all possible LOINC codes or lab orders. You can read more about how it was derived in the Preface, which you can get from:


Thanks again, Daniel. I take it the common order set is intentionally small to enable quicker deployment? Or does Regenstrief consider all the codes that were left out to be in need of review before including them?