# MedMij, BgZ, zibs and the VWS FHIR-besluit: four Dutch layers that are not one API > MedMij is patient/PHR exchange. BgZ is the Dutch patient-summary dataset. zibs are clinical models. The VWS FHIR-besluit pairs STU3+zib2017 and R4+zib2020 — MedMij is not R4-only. Author: Ala Ben Aicha Canonical page: https://alabenaicha.me/insights/fhir-nl-medmij-bgz Updated: 2026-09-19 ## Direct answer MedMij is patient/PHR exchange. BgZ is the Dutch patient-summary dataset. zibs are clinical models. The VWS FHIR-besluit pairs STU3 with zib2017 and R4 with zib2020; MedMij is not R4-only. ## Four names, four jobs Dutch FHIR conversations collapse MedMij, BgZ, zibs and the ministry FHIR decision into “the Dutch profile”. They are stacked layers. A MedMij PGO (personal health environment) that speaks BgZ is not a generic R4 Patient server, and an R4 nl-core beta is not a MedMij production package. | Layer | Owner / home | Canonical / package | What it is | What it is not | | ----------------------------------- | ----------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------- | ------------------------------------------------------ | | **zibs** (Zorginformatiebouwstenen) | Nictiz zib-centrum; [zibs.nl](https://zibs.nl/) | Clinical information models, versioned (2017, 2020, …) | **Semantic** building blocks: what a blood pressure or patient name means, independent of FHIR | Not a FHIR IG, not a REST API | | **BgZ** (Basisgegevensset Zorg) | Nictiz; [informatiestandaarden.nictiz.nl](https://informatiestandaarden.nictiz.nl/); package family `nictiz.fhir.nl.stu3.bgz` | Patient-summary **dataset** composed of zibs; FHIR STU3 profiles in `Nictiz-STU3-BgZ` | The Dutch patient-summary content that MedMij and other programmes reuse | Not MedMij itself, not IPS, not EEHRxF Patient Summary | | **MedMij** | MedMij / Nictiz; [MedMij FHIR IG](https://informatiestandaarden.nictiz.nl/wiki/MedMij:IG:V1/FHIR_IG) | STU3 packages still in production (`nictiz.fhir.nl.stu3.zib2017` 2.3.x, `medmij.fhir.nl.stu3.core`); R4 `medmij.fhir.nl.r4.core` 1.1.0 exists alongside | **Patient/PHR exchange** afsprakenstelsel: how a PGO talks to a zorgaanbieder | Not a hospital EHR interface, not already R4-only | | **VWS FHIR-besluit** (21 Oct 2022) | Ministry of Health, Welfare and Sport | Policy pairing, not a package | **STU3 + zib2017** or **R4 + zib2020**; not other FHIR versions, not mixed pairs | Not a cutover date. It does not retire MedMij STU3 | Primary sources: Nictiz information standards, the [VWS FHIR-besluit](https://confluence.hl7.org/download/attachments/104564554/FHIR%20besluit.pdf?api=v2) (21 October 2022). R4 `nictiz.fhir.nl.r4.nl-core` is published in **beta** (0.12.0-beta sequence on Simplifier). Do not treat a beta nl-core package as the MedMij production contract. ## The identifier: BSN Country-specific identifier for Dutch Patient resources is the Burgerservicenummer (BSN). HL7 Netherlands / Nictiz Patient profiles fix: `http://fhir.nl/fhir/NamingSystem/bsn` OID `2.16.840.1.113883.2.4.6.3`. Nine digits, eleven-proof. Use of BSN in care is constrained by Wbsn-z; research and apps without a processing agreement are typical reasons **not** to send it. Do not publish a real BSN. Keep the system URL and a dummy value in fixtures. A hospital MRN is an additional identifier. It does not replace BSN when the receiver is a MedMij or national Dutch FHIR endpoint. ## What to implement first 1. If the buyer is a **PGO or MedMij zorgaanbieder**: the MedMij information standard named in the contract, usually **STU3 + zib2017** BgZ. Confirm the package (`nictiz.fhir.nl.stu3.zib2017` / `nictiz.fhir.nl.stu3.bgz`) rather than assuming R4. 2. If the buyer is on an **R4 / zib2020** path: `nictiz.fhir.nl.r4.nl-core` (implementable layer) plus `nictiz.fhir.nl.r4.zib2020` (abstract zib layer). The zib2020 profiles are marked abstract; do not implement the abstract package as the wire format. 3. If the buyer says “Dutch FHIR” without naming MedMij, BgZ or a Nictiz information standard: stop and name the standard. Wegiz (mandatory exchange) names use cases; it does not by itself pick STU3 or R4. 4. For EHDS category 1, BgZ is a cousin of IPS / EU Patient Summary, not a drop-in. See [EU Core and EHDS](https://alabenaicha.me/insights/fhir-eu-core-ehds-implementation). The [country hub](https://alabenaicha.me/insights/fhir-implementation-guides-by-country) is the map. The [HL7 FHIR R4 guide](https://alabenaicha.me/insights/hl7-fhir-integration-guide) is the generic REST primer — MedMij search and zib bindings override it. ## What this is not This article is not MedMij qualification, not a Nictiz certificate, not a Wegiz legal opinion, and not permission to process BSN. Shipping STU3 BgZ profiles in a lab does not enrol you in the MedMij afsprakenstelsel. I do not perform MedMij deelnemer tests. Nothing here is clinical advice. ## Related reading * [FHIR implementation guides by country](https://alabenaicha.me/insights/fhir-implementation-guides-by-country) * [EU Core and EHDS](https://alabenaicha.me/insights/fhir-eu-core-ehds-implementation) * [HL7 FHIR R4 integration](https://alabenaicha.me/insights/hl7-fhir-integration-guide) For mapping work against MedMij or nl-core, use [HL7 FHIR integration](https://alabenaicha.me/services/hl7-fhir-integration) or [start a project](https://alabenaicha.me/contact?intent=project).