PV1-19 in HL7 v2: A Field Guide to Visit Number
PV1-19 is the field nearly every clinical result, order, and charge gets tied back to during a stay, which makes it one of the highest-stakes fields in the entire segment — and also one of the easiest to get wrong when a health system merges data from multiple source systems.
PV1-19 is the nineteenth field of the PV1 segment — a composite (CX data type) identifier that uniquely represents this specific visit or encounter, distinct from the patient's MRN.
What this field contains
Example
The 19th field (8827364501) is the unique visit number for this encounter. Synthetic patient — not a real person.
Where this trips people up
Visit numbers are frequently unique only within the facility or system that assigned them, not globally — a bare numeric value like "8827364501" can theoretically be reused at a different hospital in the same health system. Integrations that treat PV1-19 as a globally unique key without also checking the assigning authority component can accidentally merge two completely unrelated encounters the moment a second facility's data flows through the same pipeline.