HL7 v2 RXR Segment Guide: Fields, Format, and Testing Gotchas
RXA tells you a dose was given — RXR tells you how. Without a valid route, site, and device, an administration record is incomplete no matter how correct the drug and dose look, and RXR is the segment that most integrations treat as an afterthought until a route code shows up that nobody mapped.
RXR (Pharmacy/Treatment Route) records how a drug or vaccine was physically administered: the route the substance took into the body, the anatomical site where it was given, and the device used to deliver it. It follows directly after an RXA segment in pharmacy and immunization messages, and most systems only require RXR-1, but real-world feeds lean heavily on RXR-2 and RXR-3 for injectable and infused products.
The fields that actually matter in practice
Example
A synthetic RXA/RXR pair: the RXA records a 0.5 mL adult Hepatitis B dose, and the paired RXR shows it was given intramuscularly, into the left deltoid, via syringe.
Where this trips people up
Teams often build test data that only varies RXA and leaves RXR fixed to a single route/site/device combination, usually IM/deltoid/syringe. That hides bugs in how the receiving system handles oral doses with no meaningful site, infusions where RXR-3 carries a pump identifier instead of a simple device code, or nebulized treatments where RXR-2 is legitimately absent. Because RXR-2 and RXR-3 are optional in the standard, some parsers assume they can be blank without consequence — until a downstream MAR display or registry submission expects a site for every injectable and silently drops or flags the record instead.