How the ZAP Works

The ZAP (Zus Aggregated Profile) for a patient is a single place where you can see health information from your organization along with information from external data sources aggregated by Zus. Each ZAP is tied to a unique UPID (universal patient identifier) that identifies a patient across the Zus platform.

Imagine you are a care team user at Celery Health looking to reconcile a patient’s medications. You can use the patient's ZAP to see medications entered by your care team, as well as medications from external sources. These external sources include third party partner networks, other Builders on Zus treating the same patient, and Zus summarized (lens) medications derived from data across all sources.

There are several ways to access the ZAP. Clinical users can use the Zus Application, or an integration from one of our many EHR partners. Developers and analysts can also integrate ZAP data into their applications and analyses using our APIs or Data Marts.

The Universal Patient Identifier (UPID)

Zus offers its own identity mapping service,the Universal Patient Index (UPI), for what is more broadly known as a Master Patient Index. As with other MPI's, patient records submitted to Zus will be compared against all of the patient identities known to Zus, and granted an index key, or Universal Patient Identifier (UPID). This UPID will be shared across any and all patient records believed to be the same real individual.

The UPI automatically operates on all patient records in order to build towards a cohesive and national view of patient identities and medical histories. In order to safeguard the private information of our patients, our matching models err on the side of caution, requiring a surfeit of information in some cases to consider matches viable. UPI performs automatic matching and identity assignment of patient records only when enough information is present and aligned across the novel record and the existing identity. Our UPIDs are for the time being, displayed as universally unique identifier values, or 32 character hexadecimal sequences, e.g. 6738c92e-d3ec-424b-84c1-ffbbb16b3721

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Non-Permanence of Universal Patient Identifiers (UPIDs)

A UPID is not a permanent identifier for a patient. It can change due to updates to patient demographics, improved matching algorithms, and corrections to records. As new information is added and data accuracy improves, the UPID may be reassigned to better reflect the patient's identity. Users should note that the UPID assigned at one time might differ in the future due to ongoing data refinement.

Zus automatically leaves the UPID as a breadcrumb on your patient record for you to use without touching the UPI interfaces directly. The UPID identifier on a patient resource looks like this:

"identifier": [
    {
        "system": "https://zusapi.com/fhir/identifier/universal-id",
        "value": "<UPID>"
    }
]

You could query for all patient records who share a UPID in the following manner.

https://api.zusapi.com/fhir/Patient?identifier={{UPID}}

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UPI Permissions

Builder users and app clients are NOT permitted to create, modify, or delete UPI resources or identifiers. Any attempt to do so will result in a 403 error.