Search for a patient with identifier

Last updated: Feb 23, 2026

IMPLEMENTATION

HEALTH TECH VENDOR

PRODUCT OWNER

You can use this API action to retrieve a patient's record from an EHR system with a specific identifier.

Search with a patient's identifier or demographics?

You can locate a patient’s record in an EHR system with either an identifier or with demographics. So how do you know which to use and when?

Using the patient identifier:

saves time since you only populate one field instead of a handful of demographics fields; and
likely locates the correct patient since identifiers are typically more unique than patient demographics.

The catch is that you have to already have a patient identifier, like the MRN, on hand. If you do, we definitely recommend this option. We also recommend validating you found the right patient (because you don’t ever make typos, right?) by confirming the returned patient’s demographics match your patient. Once confirmed, you can start retrieving the patient's relevant clinical data.

On the flip side, using the patient demographics:

allows you as an outsider (stay gold, Ponyboy) to search a system that you don’t have access to; and
locates the patient identifier if you don't have one already.

So this back-door alternative is fantastic if you have the patient's info, minus the appropriate identifier. We can still help you find the right patient with a little extra time. Learn more about searching with patient demographics.

Use cases

This API action may be a good fit for your organization if you perform any of these use cases:

Tie patient records from your system to the patient’s record in the relevant EHR system.
Locate other patient identifiers used in different systems.
Start a search for a patient’s demographics, insurance, general clinical data, test results, prescribed medications, or vaccination history.

Supported systems

You can use this API action with the Redox FHIR® API.

Your connection's system can return results with their own FHIR® or query-based API.

Using data on demand

Your connection's system may not support a query-based data exchange, but they may still be willing to provide results with a push-based method.

However, we understand that you may not want to store all that data. Maybe you don't need all the possible results and just want to query for what you want when you need it. If so, you can use this API action via our data on demand service, which stores the connection's data so that you can query from Redox "on demand." Learn about data on demand.

Things you need to know

Not your typical Google search

System and identifier types

FHIR resource IDs

EHR-specific IDs

What's next?

Does this API action seem like a good fit for your unique workflow? Let your Technical Account Manager know! To start development, download the resource schema noted in the related action step. Then decide which data elements you need.

If you’re new to Redox, use the Quickstart guide to dive in. If you’re not engaged with our sales team yet, talk to a Redoxer to get started.

Action steps

1
Search for a patient with identifier
required

You can search for a patient with their unique identifier if you know which identifier type to use for the given EHR system.

For example, if you have the MRN, but the EHR system uses the FHIR® resource ID, you may have to search with the MRN to locate all identifiers for this patient first. Alternatively, you can search for a patient with demographics to locate the resource ID. Then, you can perform additional API actions that require the FHIR® resource ID.

This table has notes about how to use parameters for this API action specifically, but it's not exhaustive. Refer to the Patient schema for more details.

Query parameter	Required	Notes
identifier	Y	When searching by identifier, you must include the patient's unique identifier within the EHR system that you're searching for. This means you must know the unique identifier for that specific system for the search to be successful.

You typically receive either one result or none. Multiple matches may be returned depending on the identifier type that you’re using (since not all patient identifiers are unique) or your integration type.

Multi-region users

If you’re operating in Canada, you have to add the ca region to the Redox endpoint URL: https://api.ca.redoxengine.com.

Patient/_search

Select sandbox

Select format

Query

bash

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curl 'https://api.redoxengine.com/fhir/R4/redox-fhir-sandbox/Development/Patient/_search' \
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--request POST \
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--header 'Authorization: Bearer $API_TOKEN' \
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--header 'Content-Type: application/x-www-form-urlencoded' \
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--data-urlencode 'identifier=urn:redox:redox-fhir-sandbox:MR|kyHGADnvX3xbkU4V9ayaqh'

Response

json

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{
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  "id": "fc7b832c-2a3b-4b17-80e7-2dbc81109f8f",
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  "type": "searchset",
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  "entry": [
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    {
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      "search": {
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        "mode": "match",
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        "score": 1
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      },
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      "resource": {
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        "id": "81c2f5eb-f99f-40c4-b504-59483e6148d7",
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        "meta": {
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          "lastUpdated": "2020-10-29T20:06:13.429Z"
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        },
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        "name": [
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          {
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            "use": "official",
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            "given": [
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              "Keva"
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            ],
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            "family": "Green"
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          }
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        ],
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        "active": true,
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        "gender": "female",
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        "address": [
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          {
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            "use": "home",
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            "city": "Hillsboro",
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            "line": [
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              "932 Stehr Vista"
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            ],
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            "state": "OR",
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            "postalCode": "97123"
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          }
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        ],
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        "birthDate": "1995-08-26",
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        "extension": [
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          {
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            "url": "http://hl7.org/fhir/us/core/StructureDefinition/us-core-race",
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            "extension": [
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              {
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                "url": "text",
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                "valueString": "White"
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              }
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            ]
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          },
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          {
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            "url": "http://hl7.org/fhir/us/core/StructureDefinition/us-core-ethnicity",
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            "extension": [
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              {
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                "url": "ombCategory",
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                "valueCoding": {
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                  "code": "2186-5",
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                  "system": "urn:oid:2.16.840.1.113883.6.238",
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                  "display": "Non Hispanic or Latino"
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                }
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              },
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              {
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                "url": "text",
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                "valueString": "Not hispanic or latino"
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              }
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            ]
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          }
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        ],
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        "identifier": [
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          {
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            "value": "kyHGADnvX3xbkU4V9ayaqh",
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            "system": "urn:redox:redox-fhir-sandbox:MR"
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          }
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        ],
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        "resourceType": "Patient",
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        "deceasedDateTime": null
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      }
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    }
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  ],
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  "total": 1,
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  "resourceType": "Bundle"
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}

FHIR® is a registered trademark of Health Level Seven International (HL7) and is used with the permission of HL7. Use of this trademark does not constitute an endorsement of products/services by HL7®.