QBP^Q11 — Get Person Demographics

EMPI/MPI query to fetch a patient demographic record based on criteria (name, date of birth, sex, external identifiers). Cornerstone of IHE PDQ (Patient Demographics Query) and used intensively by patient portals and temporary admission modules.

Purpose

Q11 queries an EMPI (Enterprise Master Patient Index) or regional MPI to retrieve a patient identified ambiguously (search by name + DOB, by partial external identifier, by social security number). It is the "patient matching" mechanism of French GHT and the nominal query of regional platforms (e.g. ENRS, INS-NIR).

Segment structure

Structure QBP_Q11: MSH, [SFT], QPD, [RCP], [DSC].

• QPD-1 — Message Query Name: Q11^Get Person Demographics^HL70471.
• QPD-2 — Query Tag: unique identifier of the request (correlation with response).
• QPD-3 — Demographics Fields: repeatable components as @PID.x.y^value.
• RCP-1 — Query Priority: I (immediate) or D (deferred).
• RCP-2 — Quantity Limited Request: max 10 results by default.

Real-world example

Search for a patient Marie DURAND born 1979-03-15:

MSH|^~\&|EHR|HOSP02|EMPI|REG01|20260519101500||QBP^Q11^QBP_Q11|QBPQ11001|P|2.5.1|||AL|NE
QPD|Q11^Get Person Demographics^HL70471|QRY-2026-051901|@PID.5.1.1^DURAND~@PID.5.2^MARIE~@PID.7^19790315
RCP|I|10^RD&Records&HL70126

Response RSP^K21

The EMPI server responds with 1 or N PID segments. QAK-2 carries the status: OK, NF (not found), AE (application error):

MSH|^~\&|EMPI|REG01|EHR|HOSP02|20260519101501||RSP^K21^RSP_K21|RSPK21001|P|2.5.1|||AL|NE
MSA|AA|QBPQ11001
QAK|QRY-2026-051901|OK|Q11^Get Person Demographics^HL70471|1|1|0
QPD|Q11^Get Person Demographics^HL70471|QRY-2026-051901|@PID.5.1.1^DURAND~@PID.5.2^MARIE~@PID.7^19790315
PID|1||EMPI-887654321^^^EMPI^MR~123456789^^^INSEE^NH||DURAND^MARIE^^^MS.||19790315|F|||12 RUE DE LA PAIX^^PARIS^^75002^FRA

Common errors

• QPD-3 ambiguous: a name-only search often returns a hundred results. Add DOB + sex minimum.
• Accent encoding: French names with accents must be encoded as UTF-8 explicitly via MSH-18.
• RCP-2 missing: no limit, EMPI DoS risk.
• Confusion Q11 vs Q21/Q22: Q21 (Get Person Demographics + Visit) also returns active visits. Q22 (Find Candidates) returns a matching score.

Related queries

See also: ADT^A04, ADR^A19, QRY^A19.