HL7 v2 OBR-24 Field Guide: Diagnostic Serv Sect ID Codes and Common Mistakes
OBR-24 is what a results-routing engine reads to decide which worklist an order lands on — chemistry, microbiology, radiology. It's a site-defined table, not a fixed one, so an interface tuned against one hospital's code set will misroute orders the moment it connects to a second site using different values for the same department.
OBR-24 is the twenty-fourth field of the HL7 v2 OBR segment — the Diagnostic Service Section ID, a short code identifying which department or service section is expected to perform the ordered study.
Common values
Example
OBR-24 carries CH, routing this order to the chemistry section. Synthetic order — not a real patient.
Where this trips people up
Because OBR-24 draws from a locally defined table rather than a universal one, a routing rule hardcoded against one facility's values ('CH' for chemistry, say) can silently misfire against a second facility that uses a different short code for the same department. This tends to surface only during a multi-site rollout or an acquisition integration, well after the original interface passed all its single-site tests. Always confirm the actual value set with each sending facility rather than assuming it matches a prior integration.