diff --git a/api/consumer/searchDocumentReference/search_document_reference.py b/api/consumer/searchDocumentReference/search_document_reference.py
index b313e11b1..b420c7132 100644
--- a/api/consumer/searchDocumentReference/search_document_reference.py
+++ b/api/consumer/searchDocumentReference/search_document_reference.py
@@ -9,7 +9,7 @@
 from nrlf.core.logger import LogReference, logger
 from nrlf.core.model import ConnectionMetadata, ConsumerRequestParams
 from nrlf.core.response import Response, SpineErrorResponse
-from nrlf.core.validators import validate_type_system
+from nrlf.core.validators import validate_category, validate_type_system
 
 
 @request_handler(params=ConsumerRequestParams)
@@ -58,6 +58,16 @@ def handler(
             expression="type",
         )
 
+    if not validate_category(params.category):
+        logger.log(
+            LogReference.CONSEARCH002b,
+            category=params.category,
+        )  # TODO - Should update error message once permissioning by category is implemented
+        return SpineErrorResponse.INVALID_CODE_SYSTEM(
+            diagnostics="Invalid query parameter (The provided category is not valid)",
+            expression="category",
+        )
+
     custodian_id = (
         params.custodian_identifier.root.split("|", maxsplit=1)[1]
         if params.custodian_identifier
@@ -70,6 +80,9 @@ def handler(
     if params.type:
         self_link += f"&type={params.type.root}"
 
+    if params.category:
+        self_link += f"&category={params.category.root}"
+
     bundle = {
         "resourceType": "Bundle",
         "type": "searchset",
@@ -89,6 +102,7 @@ def handler(
         nhs_number=params.nhs_number,
         custodian=custodian_id,
         pointer_types=pointer_types,
+        categories=[params.category.root] if params.category else [],
     ):
         try:
             document_reference = DocumentReference.model_validate_json(result.document)
diff --git a/api/consumer/searchDocumentReference/tests/test_search_document_reference_consumer.py b/api/consumer/searchDocumentReference/tests/test_search_document_reference_consumer.py
index 72d1b70b8..1b8cd23b1 100644
--- a/api/consumer/searchDocumentReference/tests/test_search_document_reference_consumer.py
+++ b/api/consumer/searchDocumentReference/tests/test_search_document_reference_consumer.py
@@ -135,6 +135,47 @@ def test_search_document_reference_happy_path_with_type(
     }
 
 
+@mock_aws
+@mock_repository
+def test_search_document_reference_happy_path_with_category(
+    repository: DocumentPointerRepository,
+):
+    doc_ref = load_document_reference("Y05868-736253002-Valid")
+    doc_pointer = DocumentPointer.from_document_reference(doc_ref)
+    repository.create(doc_pointer)
+
+    event = create_test_api_gateway_event(
+        headers=create_headers(),
+        query_string_parameters={
+            "subject:identifier": "https://fhir.nhs.uk/Id/nhs-number|6700028191",
+            "category": "http://snomed.info/sct|734163000",
+        },
+    )
+
+    result = handler(event, create_mock_context())
+    body = result.pop("body")
+
+    assert result == {
+        "statusCode": "200",
+        "headers": default_response_headers(),
+        "isBase64Encoded": False,
+    }
+
+    parsed_body = json.loads(body)
+    assert parsed_body == {
+        "resourceType": "Bundle",
+        "type": "searchset",
+        "link": [
+            {
+                "relation": "self",
+                "url": "https://pytest.api.service.nhs.uk/record-locator/consumer/FHIR/R4/DocumentReference?subject:identifier=https://fhir.nhs.uk/Id/nhs-number|6700028191&category=http://snomed.info/sct|734163000",
+            }
+        ],
+        "total": 1,
+        "entry": [{"resource": doc_ref.model_dump(exclude_none=True)}],
+    }
+
+
 @mock_aws
 @mock_repository
 def test_search_document_reference_happy_path_with_nicip_type(
@@ -342,6 +383,51 @@ def test_search_document_reference_invalid_type(repository: DocumentPointerRepos
     }
 
 
+@mock_aws
+@mock_repository
+def test_search_document_reference_invalid_category(
+    repository: DocumentPointerRepository,
+):
+    event = create_test_api_gateway_event(
+        headers=create_headers(),
+        query_string_parameters={
+            "subject:identifier": "https://fhir.nhs.uk/Id/nhs-number|6700028191",
+            "category": "https://fhir.nhs.uk/CodeSystem/Document-Type|invalid",
+        },
+    )
+
+    result = handler(event, create_mock_context())
+    body = result.pop("body")
+
+    assert result == {
+        "statusCode": "400",
+        "headers": default_response_headers(),
+        "isBase64Encoded": False,
+    }
+
+    parsed_body = json.loads(body)
+    assert parsed_body == {
+        "resourceType": "OperationOutcome",
+        "issue": [
+            {
+                "severity": "error",
+                "code": "code-invalid",
+                "details": {
+                    "coding": [
+                        {
+                            "code": "INVALID_CODE_SYSTEM",
+                            "display": "Invalid code system",
+                            "system": "https://fhir.nhs.uk/ValueSet/Spine-ErrorOrWarningCode-1",
+                        }
+                    ]
+                },
+                "diagnostics": "Invalid query parameter (The provided category is not valid)",
+                "expression": ["category"],
+            }
+        ],
+    }
+
+
 @mock_aws
 @mock_repository
 def test_search_document_reference_invalid_json(repository: DocumentPointerRepository):
diff --git a/api/consumer/searchPostDocumentReference/search_post_document_reference.py b/api/consumer/searchPostDocumentReference/search_post_document_reference.py
index 353ebf5c5..18ac8e606 100644
--- a/api/consumer/searchPostDocumentReference/search_post_document_reference.py
+++ b/api/consumer/searchPostDocumentReference/search_post_document_reference.py
@@ -9,7 +9,7 @@
 from nrlf.core.logger import LogReference, logger
 from nrlf.core.model import ConnectionMetadata, ConsumerRequestParams
 from nrlf.core.response import Response, SpineErrorResponse
-from nrlf.core.validators import validate_type_system
+from nrlf.core.validators import validate_category, validate_type_system
 
 
 @request_handler(body=ConsumerRequestParams)
@@ -61,6 +61,16 @@ def handler(
             expression="type",
         )
 
+    if not validate_category(body.category):
+        logger.log(
+            LogReference.CONPOSTSEARCH002b,
+            type=body.category,
+        )  # TODO - Should update error message once permissioning by category is implemented
+        return SpineErrorResponse.INVALID_CODE_SYSTEM(
+            diagnostics="The provided category is not valid",
+            expression="category",
+        )
+
     custodian_id = (
         body.custodian_identifier.root.split("|", maxsplit=1)[1]
         if body.custodian_identifier
@@ -73,6 +83,9 @@ def handler(
     if body.type:
         self_link += f"&type={body.type.root}"
 
+    if body.category:
+        self_link += f"&category={body.category.root}"
+
     bundle = {
         "resourceType": "Bundle",
         "type": "searchset",
@@ -89,7 +102,10 @@ def handler(
     )
 
     for result in repository.search(
-        nhs_number=body.nhs_number, custodian=custodian_id, pointer_types=pointer_types
+        nhs_number=body.nhs_number,
+        custodian=custodian_id,
+        pointer_types=pointer_types,
+        categories=[body.category.root] if body.category else [],
     ):
         try:
             document_reference = DocumentReference.model_validate_json(result.document)
diff --git a/api/consumer/searchPostDocumentReference/tests/test_search_post_document_reference_consumer.py b/api/consumer/searchPostDocumentReference/tests/test_search_post_document_reference_consumer.py
index 016f6ebc9..3dc41ba45 100644
--- a/api/consumer/searchPostDocumentReference/tests/test_search_post_document_reference_consumer.py
+++ b/api/consumer/searchPostDocumentReference/tests/test_search_post_document_reference_consumer.py
@@ -144,6 +144,49 @@ def test_search_post_document_reference_happy_path_with_type(
     }
 
 
+@mock_aws
+@mock_repository
+def test_search_post_document_reference_happy_path_with_category(
+    repository: DocumentPointerRepository,
+):
+    doc_ref = load_document_reference("Y05868-736253002-Valid")
+    doc_pointer = DocumentPointer.from_document_reference(doc_ref)
+    repository.create(doc_pointer)
+
+    event = create_test_api_gateway_event(
+        headers=create_headers(),
+        body=json.dumps(
+            {
+                "subject:identifier": "https://fhir.nhs.uk/Id/nhs-number|6700028191",
+                "category": "http://snomed.info/sct|734163000",
+            },
+        ),
+    )
+
+    result = handler(event, create_mock_context())
+    body = result.pop("body")
+
+    assert result == {
+        "statusCode": "200",
+        "headers": default_response_headers(),
+        "isBase64Encoded": False,
+    }
+
+    parsed_body = json.loads(body)
+    assert parsed_body == {
+        "resourceType": "Bundle",
+        "type": "searchset",
+        "link": [
+            {
+                "relation": "self",
+                "url": "https://pytest.api.service.nhs.uk/record-locator/consumer/FHIR/R4/DocumentReference?subject:identifier=https://fhir.nhs.uk/Id/nhs-number|6700028191&category=http://snomed.info/sct|734163000",
+            }
+        ],
+        "total": 1,
+        "entry": [{"resource": doc_ref.model_dump(exclude_none=True)}],
+    }
+
+
 @mock_aws
 @mock_repository
 def test_search_document_reference_no_results(repository: DocumentPointerRepository):
@@ -310,6 +353,53 @@ def test_search_post_document_reference_invalid_type(
     }
 
 
+@mock_aws
+@mock_repository
+def test_search_document_reference_invalid_category(
+    repository: DocumentPointerRepository,
+):
+    event = create_test_api_gateway_event(
+        headers=create_headers(),
+        body=json.dumps(
+            {
+                "subject:identifier": "https://fhir.nhs.uk/Id/nhs-number|6700028191",
+                "category": "https://fhir.nhs.uk/CodeSystem/Document-Type|invalid",
+            }
+        ),
+    )
+
+    result = handler(event, create_mock_context())
+    body = result.pop("body")
+
+    assert result == {
+        "statusCode": "400",
+        "headers": default_response_headers(),
+        "isBase64Encoded": False,
+    }
+
+    parsed_body = json.loads(body)
+    assert parsed_body == {
+        "resourceType": "OperationOutcome",
+        "issue": [
+            {
+                "severity": "error",
+                "code": "code-invalid",
+                "details": {
+                    "coding": [
+                        {
+                            "code": "INVALID_CODE_SYSTEM",
+                            "display": "Invalid code system",
+                            "system": "https://fhir.nhs.uk/ValueSet/Spine-ErrorOrWarningCode-1",
+                        }
+                    ]
+                },
+                "diagnostics": "The provided category is not valid",
+                "expression": ["category"],
+            }
+        ],
+    }
+
+
 @mock_aws
 @mock_repository
 def test_search_post_document_reference_invalid_json(
diff --git a/api/consumer/swagger.yaml b/api/consumer/swagger.yaml
index 6e831a1bd..6356607b3 100644
--- a/api/consumer/swagger.yaml
+++ b/api/consumer/swagger.yaml
@@ -257,6 +257,7 @@ paths:
         - $ref: "#/components/parameters/subject"
         - $ref: "#/components/parameters/custodian"
         - $ref: "#/components/parameters/type"
+        - $ref: "#/components/parameters/category"
         - $ref: "#/components/parameters/nextPageToken"
         - $ref: "#/components/parameters/odsCode"
         - $ref: "#/components/parameters/odsCodeExtension"
@@ -1399,6 +1400,8 @@ components:
           $ref: "#/components/schemas/RequestQueryCustodian"
         type:
           $ref: "#/components/schemas/RequestQueryType"
+        category:
+          $ref: "#/components/schemas/RequestQueryCategory"
         next-page-token:
           $ref: "#/components/schemas/NextPageToken"
       required:
@@ -1421,6 +1424,9 @@ components:
     RequestQueryType:
       type: string
       example: "http://snomed.info/sct|736253002"
+    RequestQueryCategory:
+      type: string
+      example: "http://snomed.info/sct|103693007"
     NextPageToken:
       type: string
     RequestHeaderOdsCode:
@@ -1531,6 +1537,33 @@ components:
         invalid:
           summary: Unknown
           value: http://snomed.info/sct|410970009
+    category:
+      name: category
+      in: query
+      schema:
+        $ref: "#/components/schemas/RequestQueryCategory"
+      examples:
+        none:
+          summary: None
+          value: ""
+        SNOMED_CODES_CARE_PLAN:
+          summary: Care plan
+          value: http://snomed.info/sct|734163000
+        SNOMED_CODES_OBSERVATIONS:
+          summary: Observations
+          value: http://snomed.info/sct|1102421000000108
+        SNOMED_CODES_CLINICAL_NOTE:
+          summary: Clinical note
+          value: http://snomed.info/sct|823651000000106
+        SNOMED_CODES_DIAGNOSTIC_STUDIES_REPORT:
+          summary: Diagnostic studies report
+          value: http://snomed.info/sct|721981007
+        SNOMED_CODES_DIAGNOSTIC_PROCEDURE:
+          summary: Diagnostic procedure
+          value: http://snomed.info/sct|103693007
+        invalid:
+          summary: Unknown
+          value: http://snomed.info/sct|410970009
     nextPageToken:
       name: next-page-token
       description: |
diff --git a/api/producer/searchDocumentReference/search_document_reference.py b/api/producer/searchDocumentReference/search_document_reference.py
index 133d47fd1..d2dad8fd5 100644
--- a/api/producer/searchDocumentReference/search_document_reference.py
+++ b/api/producer/searchDocumentReference/search_document_reference.py
@@ -6,7 +6,7 @@
 from nrlf.core.logger import LogReference, logger
 from nrlf.core.model import ConnectionMetadata, ProducerRequestParams
 from nrlf.core.response import Response, SpineErrorResponse
-from nrlf.core.validators import validate_type_system
+from nrlf.core.validators import validate_category, validate_type_system
 from nrlf.producer.fhir.r4.model import Bundle, DocumentReference
 
 
@@ -59,6 +59,16 @@ def handler(
             expression="type",
         )
 
+    if not validate_category(params.category):
+        logger.log(
+            LogReference.PROSEARCH002b,
+            type=params.category,
+        )  # TODO - Should update error message once permissioning by category is implemented
+        return SpineErrorResponse.INVALID_CODE_SYSTEM(
+            diagnostics="Invalid query parameter (The provided category is not valid)",
+            expression="category",
+        )
+
     pointer_types = [params.type.root] if params.type else metadata.pointer_types
     bundle = {"resourceType": "Bundle", "type": "searchset", "total": 0, "entry": []}
 
@@ -68,6 +78,7 @@ def handler(
         custodian_suffix=metadata.ods_code_extension,
         nhs_number=params.nhs_number,
         pointer_types=pointer_types,
+        categories=[params.category.root] if params.category else [],
     )
 
     for result in repository.search(
@@ -75,6 +86,7 @@ def handler(
         custodian_suffix=metadata.ods_code_extension,
         nhs_number=params.nhs_number,
         pointer_types=pointer_types,
+        categories=[params.category.root] if params.category else [],
     ):
         try:
             document_reference = DocumentReference.model_validate_json(result.document)
diff --git a/api/producer/searchDocumentReference/tests/test_search_document_reference_producer.py b/api/producer/searchDocumentReference/tests/test_search_document_reference_producer.py
index e571bedef..7f3b89165 100644
--- a/api/producer/searchDocumentReference/tests/test_search_document_reference_producer.py
+++ b/api/producer/searchDocumentReference/tests/test_search_document_reference_producer.py
@@ -3,7 +3,7 @@
 from moto import mock_aws
 
 from api.producer.searchDocumentReference.search_document_reference import handler
-from nrlf.core.constants import PointerTypes
+from nrlf.core.constants import Categories, PointerTypes
 from nrlf.core.dynamodb.repository import DocumentPointer, DocumentPointerRepository
 from nrlf.tests.data import load_document_reference
 from nrlf.tests.dynamodb import mock_repository
@@ -203,6 +203,51 @@ def test_search_document_reference_invalid_type(repository: DocumentPointerRepos
     }
 
 
+@mock_aws
+@mock_repository
+def test_search_document_reference_invalid_category(
+    repository: DocumentPointerRepository,
+):
+    event = create_test_api_gateway_event(
+        headers=create_headers(),
+        query_string_parameters={
+            "subject:identifier": "https://fhir.nhs.uk/Id/nhs-number|6700028191",
+            "category": "https://fhir.nhs.uk/CodeSystem/Document-Type|invalid",
+        },
+    )
+
+    result = handler(event, create_mock_context())
+    body = result.pop("body")
+
+    assert result == {
+        "statusCode": "400",
+        "headers": default_response_headers(),
+        "isBase64Encoded": False,
+    }
+
+    parsed_body = json.loads(body)
+    assert parsed_body == {
+        "resourceType": "OperationOutcome",
+        "issue": [
+            {
+                "severity": "error",
+                "code": "code-invalid",
+                "details": {
+                    "coding": [
+                        {
+                            "code": "INVALID_CODE_SYSTEM",
+                            "display": "Invalid code system",
+                            "system": "https://fhir.nhs.uk/ValueSet/Spine-ErrorOrWarningCode-1",
+                        }
+                    ]
+                },
+                "diagnostics": "Invalid query parameter (The provided category is not valid)",
+                "expression": ["category"],
+            }
+        ],
+    }
+
+
 @mock_aws
 @mock_repository
 def test_search_document_reference_only_returns_custodian_pointers(
@@ -272,6 +317,41 @@ def test_search_document_reference_filters_by_type(
     }
 
 
+@mock_aws
+@mock_repository
+def test_search_document_reference_filters_by_category(
+    repository: DocumentPointerRepository,
+):
+    doc_ref = load_document_reference("Y05868-736253002-Valid")
+    doc_pointer = DocumentPointer.from_document_reference(doc_ref)
+    repository.create(doc_pointer)
+
+    event = create_test_api_gateway_event(
+        headers=create_headers(),
+        query_string_parameters={
+            "subject:identifier": "https://fhir.nhs.uk/Id/nhs-number|6700028191",
+            "category": Categories.CARE_PLAN.value,
+        },
+    )
+
+    result = handler(event, create_mock_context())
+    body = result.pop("body")
+
+    assert result == {
+        "statusCode": "200",
+        "headers": default_response_headers(),
+        "isBase64Encoded": False,
+    }
+
+    parsed_body = json.loads(body)
+    assert parsed_body == {
+        "resourceType": "Bundle",
+        "type": "searchset",
+        "total": 1,
+        "entry": [{"resource": doc_ref.model_dump(exclude_none=True)}],
+    }
+
+
 @mock_aws
 @mock_repository
 def test_search_document_reference_filters_by_pointer_types(
diff --git a/api/producer/searchPostDocumentReference/search_post_document_reference.py b/api/producer/searchPostDocumentReference/search_post_document_reference.py
index 35291de6b..12c1144e1 100644
--- a/api/producer/searchPostDocumentReference/search_post_document_reference.py
+++ b/api/producer/searchPostDocumentReference/search_post_document_reference.py
@@ -6,7 +6,7 @@
 from nrlf.core.logger import LogReference, logger
 from nrlf.core.model import ConnectionMetadata, ProducerRequestParams
 from nrlf.core.response import Response, SpineErrorResponse
-from nrlf.core.validators import validate_type_system
+from nrlf.core.validators import validate_category, validate_type_system
 from nrlf.producer.fhir.r4.model import Bundle, DocumentReference
 
 
@@ -53,6 +53,16 @@ def handler(
             expression="type",
         )
 
+    if not validate_category(body.category):
+        logger.log(
+            LogReference.PROPOSTSEARCH002b,
+            type=body.category,
+        )  # TODO - Should update error message once permissioning by category is implemented
+        return SpineErrorResponse.INVALID_CODE_SYSTEM(
+            diagnostics="The provided category is not valid",
+            expression="category",
+        )
+
     pointer_types = [body.type.root] if body.type else metadata.pointer_types
     bundle = {"resourceType": "Bundle", "type": "searchset", "total": 0, "entry": []}
 
@@ -62,6 +72,7 @@ def handler(
         custodian_suffix=metadata.ods_code_extension,
         nhs_number=body.nhs_number,
         pointer_types=pointer_types,
+        categories=[body.category.root] if body.category else [],
     )
 
     for result in repository.search(
@@ -69,6 +80,7 @@ def handler(
         custodian_suffix=metadata.ods_code_extension,
         nhs_number=body.nhs_number,
         pointer_types=pointer_types,
+        categories=[body.category.root] if body.category else [],
     ):
         try:
             document_reference = DocumentReference.model_validate_json(result.document)
diff --git a/api/producer/searchPostDocumentReference/tests/test_search_post_document_reference_producer.py b/api/producer/searchPostDocumentReference/tests/test_search_post_document_reference_producer.py
index 9fe1b7db1..66bd579a8 100644
--- a/api/producer/searchPostDocumentReference/tests/test_search_post_document_reference_producer.py
+++ b/api/producer/searchPostDocumentReference/tests/test_search_post_document_reference_producer.py
@@ -5,7 +5,7 @@
 from api.producer.searchPostDocumentReference.search_post_document_reference import (
     handler,
 )
-from nrlf.core.constants import PointerTypes
+from nrlf.core.constants import Categories, PointerTypes
 from nrlf.core.dynamodb.repository import DocumentPointer, DocumentPointerRepository
 from nrlf.tests.data import load_document_reference
 from nrlf.tests.dynamodb import mock_repository
@@ -208,6 +208,53 @@ def test_search_document_reference_invalid_type(repository: DocumentPointerRepos
     }
 
 
+@mock_aws
+@mock_repository
+def test_search_document_reference_invalid_category(
+    repository: DocumentPointerRepository,
+):
+    event = create_test_api_gateway_event(
+        headers=create_headers(),
+        body=json.dumps(
+            {
+                "subject:identifier": "https://fhir.nhs.uk/Id/nhs-number|6700028191",
+                "category": "https://fhir.nhs.uk/CodeSystem/Document-Type|invalid",
+            }
+        ),
+    )
+
+    result = handler(event, create_mock_context())
+    body = result.pop("body")
+
+    assert result == {
+        "statusCode": "400",
+        "headers": default_response_headers(),
+        "isBase64Encoded": False,
+    }
+
+    parsed_body = json.loads(body)
+    assert parsed_body == {
+        "resourceType": "OperationOutcome",
+        "issue": [
+            {
+                "severity": "error",
+                "code": "code-invalid",
+                "details": {
+                    "coding": [
+                        {
+                            "code": "INVALID_CODE_SYSTEM",
+                            "display": "Invalid code system",
+                            "system": "https://fhir.nhs.uk/ValueSet/Spine-ErrorOrWarningCode-1",
+                        }
+                    ]
+                },
+                "diagnostics": "The provided category is not valid",
+                "expression": ["category"],
+            }
+        ],
+    }
+
+
 @mock_aws
 @mock_repository
 def test_search_document_reference_only_returns_custodian_pointers(
@@ -281,6 +328,43 @@ def test_search_document_reference_filters_by_type(
     }
 
 
+@mock_aws
+@mock_repository
+def test_search_document_reference_filters_by_category(
+    repository: DocumentPointerRepository,
+):
+    doc_ref = load_document_reference("Y05868-736253002-Valid")
+    doc_pointer = DocumentPointer.from_document_reference(doc_ref)
+    repository.create(doc_pointer)
+
+    event = create_test_api_gateway_event(
+        headers=create_headers(),
+        body=json.dumps(
+            {
+                "subject:identifier": "https://fhir.nhs.uk/Id/nhs-number|6700028191",
+                "category": Categories.CARE_PLAN.value,
+            }
+        ),
+    )
+
+    result = handler(event, create_mock_context())
+    body = result.pop("body")
+
+    assert result == {
+        "statusCode": "200",
+        "headers": default_response_headers(),
+        "isBase64Encoded": False,
+    }
+
+    parsed_body = json.loads(body)
+    assert parsed_body == {
+        "resourceType": "Bundle",
+        "type": "searchset",
+        "total": 1,
+        "entry": [{"resource": doc_ref.model_dump(exclude_none=True)}],
+    }
+
+
 @mock_aws
 @mock_repository
 def test_search_document_reference_filters_by_pointer_types(
diff --git a/api/producer/swagger.yaml b/api/producer/swagger.yaml
index bea387d33..b3316d199 100644
--- a/api/producer/swagger.yaml
+++ b/api/producer/swagger.yaml
@@ -396,6 +396,7 @@ paths:
       parameters:
         - $ref: "#/components/parameters/subject"
         - $ref: "#/components/parameters/type"
+        - $ref: "#/components/parameters/category"
         - $ref: "#/components/parameters/nextPageToken"
         - $ref: "#/components/parameters/odsCode"
         - $ref: "#/components/parameters/odsCodeExtension"
@@ -1935,6 +1936,8 @@ components:
           $ref: "#/components/schemas/RequestQuerySubject"
         type:
           $ref: "#/components/schemas/RequestQueryType"
+        category:
+          $ref: "#/components/schemas/RequestQueryCategory"
         next-page-token:
           $ref: "#/components/schemas/NextPageToken"
     RequestQuerySubject:
@@ -1944,6 +1947,9 @@ components:
     RequestQueryType:
       type: string
       example: "http://snomed.info/sct|736253002"
+    RequestQueryCategory:
+      type: string
+      example: "http://snomed.info/sct|103693007"
     NextPageToken:
       type: string
     RequestHeaderOdsCode:
@@ -2038,6 +2044,33 @@ components:
         invalid:
           summary: Unknown
           value: http://snomed.info/sct|410970009
+    category:
+      name: category
+      in: query
+      schema:
+        $ref: "#/components/schemas/RequestQueryCategory"
+      examples:
+        none:
+          summary: None
+          value: ""
+        SNOMED_CODES_CARE_PLAN:
+          summary: Care plan
+          value: http://snomed.info/sct|734163000
+        SNOMED_CODES_OBSERVATIONS:
+          summary: Observations
+          value: http://snomed.info/sct|1102421000000108
+        SNOMED_CODES_CLINICAL_NOTE:
+          summary: Clinical note
+          value: http://snomed.info/sct|823651000000106
+        SNOMED_CODES_DIAGNOSTIC_STUDIES_REPORT:
+          summary: Diagnostic studies report
+          value: http://snomed.info/sct|721981007
+        SNOMED_CODES_DIAGNOSTIC_PROCEDURE:
+          summary: Diagnostic procedure
+          value: http://snomed.info/sct|103693007
+        invalid:
+          summary: Unknown
+          value: http://snomed.info/sct|410970009
     nextPageToken:
       name: next-page-token
       in: query
diff --git a/layer/nrlf/consumer/fhir/r4/model.py b/layer/nrlf/consumer/fhir/r4/model.py
index 4af54348d..061754db2 100644
--- a/layer/nrlf/consumer/fhir/r4/model.py
+++ b/layer/nrlf/consumer/fhir/r4/model.py
@@ -1,6 +1,6 @@
 # generated by datamodel-codegen:
 #   filename:  swagger.yaml
-#   timestamp: 2024-11-04T11:43:16+00:00
+#   timestamp: 2024-11-10T19:12:31+00:00
 
 from __future__ import annotations
 
@@ -397,6 +397,10 @@ class RequestQueryType(RootModel[str]):
     root: Annotated[str, Field(examples=["http://snomed.info/sct|736253002"])]
 
 
+class RequestQueryCategory(RootModel[str]):
+    root: Annotated[str, Field(examples=["http://snomed.info/sct|103693007"])]
+
+
 class NextPageToken(RootModel[str]):
     root: str
 
@@ -435,6 +439,7 @@ class RequestParams(BaseModel):
         Optional[RequestQueryCustodian], Field(alias="custodian:identifier")
     ] = None
     type: Optional[RequestQueryType] = None
+    category: Optional[RequestQueryCategory] = None
     next_page_token: Annotated[
         Optional[NextPageToken], Field(alias="next-page-token")
     ] = None
diff --git a/layer/nrlf/core/dynamodb/repository.py b/layer/nrlf/core/dynamodb/repository.py
index 8b1026bbb..a65931ccb 100644
--- a/layer/nrlf/core/dynamodb/repository.py
+++ b/layer/nrlf/core/dynamodb/repository.py
@@ -218,6 +218,7 @@ def search(
         custodian: Optional[str] = None,
         custodian_suffix: Optional[str] = None,
         pointer_types: Optional[List[str]] = [],
+        categories: Optional[List[str]] = [],
     ) -> Iterator[DocumentPointer]:
         """"""
         logger.log(
@@ -238,9 +239,28 @@ def search(
             patient_sort = f"C#{category_id}#T#{type_id}"
             key_conditions.append("begins_with(patient_sort, :patient_sort)")
             expression_values[":patient_sort"] = patient_sort
+        else:
+            # Handle single/multiple categories and pointer types with filter expressions
+            if len(categories) == 1:
+                split_category = categories[0].split("|")
+                category_id = (
+                    SYSTEM_SHORT_IDS[split_category[0]] + "-" + split_category[1]
+                )
+                patient_sort = f"C#{category_id}"
+                key_conditions.append("begins_with(patient_sort, :patient_sort)")
+                expression_values[":patient_sort"] = patient_sort
+
+            if len(categories) > 1:
+                expression_names["#category"] = "category"
+                category_filters = [
+                    f"#category = :category_{i}" for i in range(len(categories))
+                ]
+                category_filter_values = {
+                    f":category_{i}": categories[i] for i in range(len(categories))
+                }
+                filter_expressions.append(f"({' OR '.join(category_filters)})")
+                expression_values.update(category_filter_values)
 
-        # Handle multiple categories and pointer types with filter expressions
-        if len(pointer_types) > 1:
             expression_names["#pointer_type"] = "type"
             types_filters = [
                 f"#pointer_type = :type_{i}" for i in range(len(pointer_types))
diff --git a/layer/nrlf/core/log_references.py b/layer/nrlf/core/log_references.py
index 095a1e704..a140b7164 100644
--- a/layer/nrlf/core/log_references.py
+++ b/layer/nrlf/core/log_references.py
@@ -175,6 +175,9 @@ class LogReference(Enum):
     CONSEARCH002 = _Reference(
         "INFO", "Invalid document type provided in the query parameters"
     )
+    CONSEARCH002b = _Reference(
+        "INFO", "Invalid document category provided in the query parameters"
+    )
     CONSEARCH003 = _Reference("DEBUG", "Performing search by NHS number")
     CONSEARCH004 = _Reference(
         "DEBUG", "Parsed DocumentReference and added to search results"
@@ -196,6 +199,9 @@ class LogReference(Enum):
     CONPOSTSEARCH002 = _Reference(
         "INFO", "Invalid document type provided in the request body"
     )
+    CONPOSTSEARCH002b = _Reference(
+        "INFO", "Invalid document category provided in the request body"
+    )
     CONPOSTSEARCH003 = _Reference("DEBUG", "Performing search by NHS number")
     CONPOSTSEARCH004 = _Reference(
         "DEBUG", "Parsed DocumentReference and added to search results"
@@ -350,12 +356,15 @@ class LogReference(Enum):
     PROSEARCH002 = _Reference(
         "INFO", "Invalid document type provided in the query parameters"
     )
+    PROSEARCH002b = _Reference(
+        "INFO", "Invalid document category provided in the query parameters"
+    )
     PROSEARCH003 = _Reference("DEBUG", "Performing search by custodian")
     PROSEARCH004 = _Reference(
         "DEBUG", "Parsed DocumentReference and added to search results"
     )
     PROSEARCH005 = _Reference(
-        "EXCEPTION", "The DocumentReference esource could not be parsed"
+        "EXCEPTION", "The DocumentReference resource could not be parsed"
     )
     PROSEARCH999 = _Reference(
         "INFO", "Successfully completed producer searchDocumentReference"
@@ -371,6 +380,9 @@ class LogReference(Enum):
     PROPOSTSEARCH002 = _Reference(
         "INFO", "Invalid document type provided in the request body"
     )
+    PROPOSTSEARCH002b = _Reference(
+        "INFO", "Invalid document category provided in the request body"
+    )
     PROPOSTSEARCH003 = _Reference("DEBUG", "Performing search by custodian")
     PROPOSTSEARCH004 = _Reference(
         "DEBUG", "Parsed DocumentReference and added to search results"
diff --git a/layer/nrlf/core/model.py b/layer/nrlf/core/model.py
index 85c6b4f1f..05b3e5245 100644
--- a/layer/nrlf/core/model.py
+++ b/layer/nrlf/core/model.py
@@ -22,7 +22,7 @@ def nhs_number(self) -> Union[str, None]:
 
 
 class ProducerRequestParams(producer_model.RequestParams, _NhsNumberMixin):
-    pass
+    model_config = {"extra": "forbid"}
 
 
 class ConsumerRequestParams(consumer_model.RequestParams, _NhsNumberMixin):
diff --git a/layer/nrlf/core/tests/test_model.py b/layer/nrlf/core/tests/test_model.py
index ac254c405..07641989e 100644
--- a/layer/nrlf/core/tests/test_model.py
+++ b/layer/nrlf/core/tests/test_model.py
@@ -1,3 +1,6 @@
+import pytest
+from pydantic import ValidationError
+
 from nrlf.core.model import (
     ConnectionMetadata,
     ConsumerRequestParams,
@@ -64,6 +67,7 @@ def test_consumer_request_params():
             "subject:identifier": "https://fhir.nhs.uk/Id/nhs-number|9999999999",
             "custodian:identifier": "https://fhir.nhs.uk/Id/ods-organization-code|test",
             "type": "test-type",
+            "category": "test-category",
             "next-page-token": "page-token",
         }
     )
@@ -90,6 +94,28 @@ def test_consumer_request_params():
     assert params.nhs_number == "9999999999"
 
 
+def test_producer_request_params_extra_fields():
+    with pytest.raises(ValidationError):
+        ProducerRequestParams.model_validate(
+            {
+                "subject:identifier": "https://fhir.nhs.uk/Id/nhs-number|9999999999",
+                "type": "test-type",
+                "extra_field": "extra_value",
+            }
+        )
+
+
+def test_consumer_request_params_extra_fields():
+    with pytest.raises(ValidationError):
+        ConsumerRequestParams.model_validate(
+            {
+                "subject:identifier": "https://fhir.nhs.uk/Id/nhs-number|9999999999",
+                "type": "test-type",
+                "extra_field": "extra_value",
+            }
+        )
+
+
 def test_count_request_params():
     params = CountRequestParams.model_validate(
         {
diff --git a/layer/nrlf/core/validators.py b/layer/nrlf/core/validators.py
index 0974e403e..45627ccc7 100644
--- a/layer/nrlf/core/validators.py
+++ b/layer/nrlf/core/validators.py
@@ -4,8 +4,14 @@
 
 from pydantic import ValidationError
 
+from nrlf.consumer.fhir.r4.model import RequestQueryCategory
 from nrlf.core.codes import SpineErrorConcept
-from nrlf.core.constants import CATEGORY_ATTRIBUTES, ODS_SYSTEM, REQUIRED_CREATE_FIELDS
+from nrlf.core.constants import (
+    CATEGORY_ATTRIBUTES,
+    ODS_SYSTEM,
+    REQUIRED_CREATE_FIELDS,
+    Categories,
+)
 from nrlf.core.errors import ParseError
 from nrlf.core.logger import LogReference, logger
 from nrlf.core.types import DocumentReference, OperationOutcomeIssue, RequestQueryType
@@ -29,6 +35,17 @@ def validate_type_system(
     return type_system in pointer_type_systems
 
 
+# TODO - Validate category is in set permissions once permissioning by category is done.
+def validate_category(category_: Optional[RequestQueryCategory]) -> bool:
+    """
+    Validates if the given category is valid.
+    """
+    if not category_:
+        return True
+
+    return category_.root in Categories.list()
+
+
 @dataclass
 class ValidationResult:
     resource: DocumentReference
diff --git a/layer/nrlf/producer/fhir/r4/model.py b/layer/nrlf/producer/fhir/r4/model.py
index ecb14c05c..d8ad9f87f 100644
--- a/layer/nrlf/producer/fhir/r4/model.py
+++ b/layer/nrlf/producer/fhir/r4/model.py
@@ -1,6 +1,6 @@
 # generated by datamodel-codegen:
 #   filename:  swagger.yaml
-#   timestamp: 2024-11-04T11:43:12+00:00
+#   timestamp: 2024-11-10T19:12:31+00:00
 
 from __future__ import annotations
 
@@ -387,6 +387,10 @@ class RequestQueryType(RootModel[str]):
     root: Annotated[str, Field(examples=["http://snomed.info/sct|736253002"])]
 
 
+class RequestQueryCategory(RootModel[str]):
+    root: Annotated[str, Field(examples=["http://snomed.info/sct|103693007"])]
+
+
 class NextPageToken(RootModel[str]):
     root: str
 
@@ -422,6 +426,7 @@ class RequestParams(BaseModel):
         Optional[RequestQuerySubject], Field(alias="subject:identifier")
     ] = None
     type: Optional[RequestQueryType] = None
+    category: Optional[RequestQueryCategory] = None
     next_page_token: Annotated[
         Optional[NextPageToken], Field(alias="next-page-token")
     ] = None
diff --git a/layer/nrlf/producer/fhir/r4/strict_model.py b/layer/nrlf/producer/fhir/r4/strict_model.py
index 91bdcfe36..c74b28ab5 100644
--- a/layer/nrlf/producer/fhir/r4/strict_model.py
+++ b/layer/nrlf/producer/fhir/r4/strict_model.py
@@ -1,6 +1,6 @@
 # generated by datamodel-codegen:
 #   filename:  swagger.yaml
-#   timestamp: 2024-11-04T11:43:14+00:00
+#   timestamp: 2024-11-10T19:12:31+00:00
 
 from __future__ import annotations
 
@@ -342,6 +342,10 @@ class RequestQueryType(RootModel[StrictStr]):
     root: Annotated[StrictStr, Field(examples=["http://snomed.info/sct|736253002"])]
 
 
+class RequestQueryCategory(RootModel[StrictStr]):
+    root: Annotated[StrictStr, Field(examples=["http://snomed.info/sct|103693007"])]
+
+
 class NextPageToken(RootModel[StrictStr]):
     root: StrictStr
 
@@ -371,6 +375,7 @@ class RequestParams(BaseModel):
         Optional[RequestQuerySubject], Field(alias="subject:identifier")
     ] = None
     type: Optional[RequestQueryType] = None
+    category: Optional[RequestQueryCategory] = None
     next_page_token: Annotated[
         Optional[NextPageToken], Field(alias="next-page-token")
     ] = None
diff --git a/swagger/consumer-static/components.yaml b/swagger/consumer-static/components.yaml
index 8201e93fc..be736a02d 100644
--- a/swagger/consumer-static/components.yaml
+++ b/swagger/consumer-static/components.yaml
@@ -36,6 +36,11 @@ components:
       in: query
       schema:
         $ref: "#/components/schemas/RequestQueryType"
+    category:
+      name: category
+      in: query
+      schema:
+        $ref: "#/components/schemas/RequestQueryCategory"
     nextPageToken:
       name: next-page-token
       description: |
@@ -131,6 +136,8 @@ components:
           $ref: "#/components/schemas/RequestQueryCustodian"
         type:
           $ref: "#/components/schemas/RequestQueryType"
+        category:
+          $ref: "#/components/schemas/RequestQueryCategory"
         next-page-token:
           $ref: "#/components/schemas/NextPageToken"
       required:
@@ -151,6 +158,8 @@ components:
       example: "https://fhir.nhs.uk/Id/ods-organization-code|Y05868"
     RequestQueryType:
       type: string
+    RequestQueryCategory:
+      type: string
     NextPageToken:
       type: string
     RequestHeaderOdsCode:
diff --git a/swagger/consumer-static/narrative.yaml b/swagger/consumer-static/narrative.yaml
index 0250bd219..a349758ea 100644
--- a/swagger/consumer-static/narrative.yaml
+++ b/swagger/consumer-static/narrative.yaml
@@ -624,6 +624,8 @@ components:
       example: "https://fhir.nhs.uk/Id/ods-organization-code|Y05868"
     RequestQueryType:
       example: "http://snomed.info/sct|736253002"
+    RequestQueryCategory:
+      example: "http://snomed.info/sct|734163000"
 
   parameters:
     id:
diff --git a/swagger/producer-static/components.yaml b/swagger/producer-static/components.yaml
index 80e027ecb..22a096326 100644
--- a/swagger/producer-static/components.yaml
+++ b/swagger/producer-static/components.yaml
@@ -18,6 +18,11 @@ components:
       in: query
       schema:
         $ref: "#/components/schemas/RequestQueryType"
+    category:
+      name: type
+      in: query
+      schema:
+        $ref: "#/components/schemas/RequestQueryCategory"
     nextPageToken:
       name: next-page-token
       in: query
@@ -181,6 +186,8 @@ components:
           $ref: "#/components/schemas/RequestQuerySubject"
         type:
           $ref: "#/components/schemas/RequestQueryType"
+        category:
+          $ref: "#/components/schemas/RequestQueryCategory"
         next-page-token:
           $ref: "#/components/schemas/NextPageToken"
     RequestQuerySubject:
@@ -188,6 +195,8 @@ components:
       pattern: ^https\:\/\/fhir\.nhs\.uk\/Id\/nhs-number\|(\d+)$
     RequestQueryType:
       type: string
+    RequestQueryCategory:
+      type: string
     NextPageToken:
       type: string
     RequestHeaderOdsCode:
diff --git a/swagger/producer-static/narrative.yaml b/swagger/producer-static/narrative.yaml
index 6316c581c..4341faf86 100644
--- a/swagger/producer-static/narrative.yaml
+++ b/swagger/producer-static/narrative.yaml
@@ -1195,6 +1195,8 @@ components:
       example: "https://fhir.nhs.uk/Id/nhs-number|4409815415"
     RequestQueryType:
       example: "http://snomed.info/sct|736253002"
+    RequestQueryCategory:
+      example: "http://snomed.info/sct|734163000"
     RequestHeaderRequestId:
       example: 60E0B220-8136-4CA5-AE46-1D97EF59D068
     RequestHeaderCorrelationId:
diff --git a/tests/features/consumer/searchDocumentReference-failure.feature b/tests/features/consumer/searchDocumentReference-failure.feature
index 9865bc226..8ed4300e6 100644
--- a/tests/features/consumer/searchDocumentReference-failure.feature
+++ b/tests/features/consumer/searchDocumentReference-failure.feature
@@ -191,3 +191,31 @@ Feature: Consumer - searchDocumentReference - Failure Scenarios
         "diagnostics": "Your organisation 'RX898' does not have permission to access this resource. Contact the onboarding team."
       }
       """
+
+  Scenario: Search rejects request with invalid category system
+    Given the application 'DataShare' (ID 'z00z-y11y-x22x') is registered to access the API
+    And the organisation 'RX898' is authorised to access pointer types:
+      | system                 | value     |
+      | http://snomed.info/sct | 736253002 |
+    When consumer 'RX898' searches for DocumentReferences with parameters:
+      | parameter | value                                |
+      | subject   | 9278693472                           |
+      | category  | http://incorrect.info/sct\|736253002 |
+    Then the response status code is 400
+    And the response is an OperationOutcome with 1 issue
+    And the OperationOutcome contains the issue:
+      """
+      {
+        "severity": "error",
+        "code": "code-invalid",
+        "details": {
+          "coding": [{
+            "system": "https://fhir.nhs.uk/ValueSet/Spine-ErrorOrWarningCode-1",
+            "code": "INVALID_CODE_SYSTEM",
+            "display": "Invalid code system"
+          }]
+        },
+        "diagnostics": "Invalid query parameter (The provided category is not valid)",
+        "expression": ["category"]
+      }
+      """
diff --git a/tests/features/consumer/searchDocumentReference-success.feature b/tests/features/consumer/searchDocumentReference-success.feature
index 287e91d20..960dfb823 100644
--- a/tests/features/consumer/searchDocumentReference-success.feature
+++ b/tests/features/consumer/searchDocumentReference-success.feature
@@ -271,6 +271,78 @@ Feature: Consumer - searchDocumentReference - Success Scenarios
     And the Bundle has a total of 0
     And the Bundle has 0 entry
 
+  Scenario: Search for multiple DocumentReferences by NHS number and Category
+    Given the application 'DataShare' (ID 'z00z-y11y-x22x') is registered to access the API
+    And the organisation 'RX898' is authorised to access pointer types:
+      | system                 | value            |
+      | http://snomed.info/sct | 736253002        |
+      | http://snomed.info/sct | 1363501000000100 |
+    And a DocumentReference resource exists with values:
+      | property    | value                                 |
+      | id          | 02V-1111111111-SearchMultipleRefTest1 |
+      | subject     | 9278693472                            |
+      | status      | current                               |
+      | type        | 736253002                             |
+      | category    | 734163000                             |
+      | contentType | application/pdf                       |
+      | url         | https://example.org/my-doc-1.pdf      |
+      | custodian   | 02V                                   |
+      | author      | 02V                                   |
+    And a DocumentReference resource exists with values:
+      | property    | value                                 |
+      | id          | 02V-1111111111-SearchMultipleRefTest2 |
+      | subject     | 9278693472                            |
+      | status      | current                               |
+      | type        | 736253002                             |
+      | category    | 734163000                             |
+      | contentType | application/pdf                       |
+      | url         | https://example.org/my-doc-2.pdf      |
+      | custodian   | 02V                                   |
+      | author      | 02V                                   |
+    And a DocumentReference resource exists with values:
+      | property    | value                                 |
+      | id          | 02V-1111111111-SearchMultipleRefTest3 |
+      | subject     | 9278693472                            |
+      | status      | current                               |
+      | type        | 1363501000000100                      |
+      | category    | 1102421000000108                      |
+      | contentType | application/pdf                       |
+      | url         | https://example.org/my-doc-3.pdf      |
+      | custodian   | 02V                                   |
+      | author      | 02V                                   |
+    When consumer 'RX898' searches for DocumentReferences with parameters:
+      | parameter | value                             |
+      | subject   | 9278693472                        |
+      | category  | http://snomed.info/sct\|734163000 |
+    Then the response status code is 200
+    And the response is a searchset Bundle
+    And the Bundle has a self link matching 'DocumentReference?subject:identifier=https://fhir.nhs.uk/Id/nhs-number|9278693472&category=http://snomed.info/sct|734163000'
+    And the Bundle has a total of 2
+    And the Bundle has 2 entries
+    And the Bundle contains an DocumentReference with values
+      | property    | value                                 |
+      | id          | 02V-1111111111-SearchMultipleRefTest1 |
+      | subject     | 9278693472                            |
+      | status      | current                               |
+      | type        | 736253002                             |
+      | category    | 734163000                             |
+      | contentType | application/pdf                       |
+      | url         | https://example.org/my-doc-1.pdf      |
+      | custodian   | 02V                                   |
+      | author      | 02V                                   |
+    And the Bundle contains an DocumentReference with values
+      | property    | value                                 |
+      | id          | 02V-1111111111-SearchMultipleRefTest2 |
+      | subject     | 9278693472                            |
+      | status      | current                               |
+      | type        | 736253002                             |
+      | category    | 734163000                             |
+      | contentType | application/pdf                       |
+      | url         | https://example.org/my-doc-2.pdf      |
+      | custodian   | 02V                                   |
+      | author      | 02V                                   |
+    And the Bundle does not contain a DocumentReference with ID '02V-1111111111-SearchMultipleRefTest3'
+
 # No pointers found - done
 # Pointers exist but no permissions - covered in failure scenarios
 # Search by custodian - done
diff --git a/tests/features/consumer/searchPostDocumentReference-failure.feature b/tests/features/consumer/searchPostDocumentReference-failure.feature
index e4754e67c..8f5b507bd 100644
--- a/tests/features/consumer/searchPostDocumentReference-failure.feature
+++ b/tests/features/consumer/searchPostDocumentReference-failure.feature
@@ -191,3 +191,32 @@ Feature: Consumer - searchDocumentReference - Failure Scenarios
         "diagnostics": "Your organisation 'RX898' does not have permission to access this resource. Contact the onboarding team."
       }
       """
+
+  Scenario: Search rejects request with category system they are not allowed to use
+    Given the application 'DataShare' (ID 'z00z-y11y-x22x') is registered to access the API
+    And the organisation 'RX898' is authorised to access pointer types:
+      | system                 | value            |
+      | http://snomed.info/sct | 736253002        |
+      | http://snomed.info/sct | 1363501000000100 |
+    When consumer 'RX898' searches for DocumentReferences using POST with request body:
+      | key      | value                                |
+      | subject  | 9278693472                           |
+      | category | http://incorrect.info/sct\|736253002 |
+    Then the response status code is 400
+    And the response is an OperationOutcome with 1 issue
+    And the OperationOutcome contains the issue:
+      """
+      {
+        "severity": "error",
+        "code": "code-invalid",
+        "details": {
+          "coding": [{
+            "system": "https://fhir.nhs.uk/ValueSet/Spine-ErrorOrWarningCode-1",
+            "code": "INVALID_CODE_SYSTEM",
+            "display": "Invalid code system"
+          }]
+        },
+        "diagnostics": "The provided category is not valid",
+        "expression": ["category"]
+      }
+      """
diff --git a/tests/features/consumer/searchPostDocumentReference-success.feature b/tests/features/consumer/searchPostDocumentReference-success.feature
index 529f27df5..27d3fff18 100644
--- a/tests/features/consumer/searchPostDocumentReference-success.feature
+++ b/tests/features/consumer/searchPostDocumentReference-success.feature
@@ -242,3 +242,74 @@ Feature: Consumer - searchDocumentReference - Success Scenarios
     And the Bundle has a self link matching 'DocumentReference?subject:identifier=https://fhir.nhs.uk/Id/nhs-number|9278693472&custodian:identifier=https://fhir.nhs.uk/Id/ods-organization-code|RX898'
     And the Bundle has a total of 0
     And the Bundle has 0 entry
+
+  Scenario: Search for multiple DocumentReferences by NHS number and Category
+    Given the application 'DataShare' (ID 'z00z-y11y-x22x') is registered to access the API
+    And the organisation 'RX898' is authorised to access pointer types:
+      | system                 | value            |
+      | http://snomed.info/sct | 736253002        |
+      | http://snomed.info/sct | 1363501000000100 |
+    And a DocumentReference resource exists with values:
+      | property    | value                                 |
+      | id          | X26-1111111111-SearchMultipleRefTest1 |
+      | subject     | 9278693472                            |
+      | status      | current                               |
+      | type        | 736253002                             |
+      | category    | 734163000                             |
+      | contentType | application/pdf                       |
+      | url         | https://example.org/my-doc-1.pdf      |
+      | custodian   | X26                                   |
+      | author      | X26                                   |
+    And a DocumentReference resource exists with values:
+      | property    | value                                 |
+      | id          | X26-1111111111-SearchMultipleRefTest2 |
+      | subject     | 9278693472                            |
+      | status      | current                               |
+      | type        | 736253002                             |
+      | category    | 734163000                             |
+      | contentType | application/pdf                       |
+      | url         | https://example.org/my-doc-2.pdf      |
+      | custodian   | X26                                   |
+      | author      | X26                                   |
+    And a DocumentReference resource exists with values:
+      | property    | value                                 |
+      | id          | x26-1111111111-SearchMultipleRefTest3 |
+      | subject     | 9278693472                            |
+      | status      | current                               |
+      | type        | 1363501000000100                      |
+      | category    | 1102421000000108                      |
+      | contentType | application/pdf                       |
+      | url         | https://example.org/my-doc-3.pdf      |
+      | custodian   | x26                                   |
+      | author      | x26                                   |
+    When consumer 'RX898' searches for DocumentReferences using POST with request body:
+      | key      | value                             |
+      | subject  | 9278693472                        |
+      | category | http://snomed.info/sct\|734163000 |
+    Then the response status code is 200
+    And the response is a searchset Bundle
+    And the Bundle has a total of 2
+    And the Bundle has 2 entries
+    And the Bundle contains an DocumentReference with values
+      | property    | value                                 |
+      | id          | X26-1111111111-SearchMultipleRefTest1 |
+      | subject     | 9278693472                            |
+      | status      | current                               |
+      | type        | 736253002                             |
+      | category    | 734163000                             |
+      | contentType | application/pdf                       |
+      | url         | https://example.org/my-doc-1.pdf      |
+      | custodian   | X26                                   |
+      | author      | X26                                   |
+    And the Bundle contains an DocumentReference with values
+      | property    | value                                 |
+      | id          | X26-1111111111-SearchMultipleRefTest2 |
+      | subject     | 9278693472                            |
+      | status      | current                               |
+      | type        | 736253002                             |
+      | category    | 734163000                             |
+      | contentType | application/pdf                       |
+      | url         | https://example.org/my-doc-2.pdf      |
+      | custodian   | X26                                   |
+      | author      | X26                                   |
+    And the Bundle does not contain a DocumentReference with ID 'x26-1111111111-SearchMultipleRefTest3'
diff --git a/tests/performance/constants.js b/tests/performance/constants.js
index 3cd571e76..668cc9fb3 100644
--- a/tests/performance/constants.js
+++ b/tests/performance/constants.js
@@ -25,3 +25,10 @@ export const POINTER_TYPES = [
   "824321000000109",
   "2181441000000107",
 ];
+export const CATEGORIES = [
+  "734163000",
+  "1102421000000108",
+  "823651000000106",
+  "721981007",
+  "103693007",
+];
diff --git a/tests/performance/consumer/baseline.js b/tests/performance/consumer/baseline.js
index cc05b0204..ffa06c58a 100644
--- a/tests/performance/consumer/baseline.js
+++ b/tests/performance/consumer/baseline.js
@@ -41,6 +41,17 @@ export const options = {
         { target: 5, duration: "1m" },
       ],
     },
+    searchDocumentReferenceByCategory: {
+      exec: "searchDocumentReferenceByCategory",
+      executor: "ramping-arrival-rate",
+      startRate: 1,
+      timeUnit: "1s",
+      preAllocatedVUs: 5,
+      stages: [
+        { target: 5, duration: "30s" },
+        { target: 5, duration: "1m" },
+      ],
+    },
     searchPostDocumentReference: {
       exec: "searchPostDocumentReference",
       executor: "ramping-arrival-rate",
@@ -52,5 +63,16 @@ export const options = {
         { target: 5, duration: "1m" },
       ],
     },
+    searchPostDocumentReferenceByCategory: {
+      exec: "searchPostDocumentReferenceByCategory",
+      executor: "ramping-arrival-rate",
+      startRate: 1,
+      timeUnit: "1s",
+      preAllocatedVUs: 5,
+      stages: [
+        { target: 5, duration: "30s" },
+        { target: 5, duration: "1m" },
+      ],
+    },
   },
 };
diff --git a/tests/performance/consumer/client.js b/tests/performance/consumer/client.js
index 64e22d799..7f5ac6031 100644
--- a/tests/performance/consumer/client.js
+++ b/tests/performance/consumer/client.js
@@ -3,6 +3,7 @@ import {
   POINTER_IDS,
   POINTER_TYPES,
   ODS_CODE,
+  CATEGORIES,
 } from "../constants.js";
 import http from "k6/http";
 import { check } from "k6";
@@ -82,6 +83,27 @@ export function searchDocumentReference() {
   checkResponse(res);
 }
 
+export function searchDocumentReferenceByCategory() {
+  const nhsNumber = NHS_NUMBERS[Math.floor(Math.random() * NHS_NUMBERS.length)];
+  const randomCategory =
+    CATEGORIES[Math.floor(Math.random() * CATEGORIES.length)];
+
+  const identifier = encodeURIComponent(
+    `https://fhir.nhs.uk/Id/nhs-number|${nhsNumber}`
+  );
+  const category = encodeURIComponent(
+    `http://snomed.info/sct|${randomCategory}`
+  );
+
+  const res = http.get(
+    `https://${__ENV.HOST}/consumer/DocumentReference?subject:identifier=${identifier}&category=${category}`,
+    {
+      headers: getHeaders(),
+    }
+  );
+  checkResponse(res);
+}
+
 export function searchPostDocumentReference() {
   const nhsNumber = NHS_NUMBERS[Math.floor(Math.random() * NHS_NUMBERS.length)];
   const pointer_type =
@@ -101,3 +123,22 @@ export function searchPostDocumentReference() {
   );
   checkResponse(res);
 }
+
+export function searchPostDocumentReferenceByCategory() {
+  const nhsNumber = NHS_NUMBERS[Math.floor(Math.random() * NHS_NUMBERS.length)];
+  const category = CATEGORIES[Math.floor(Math.random() * CATEGORIES.length)];
+
+  const body = JSON.stringify({
+    "subject:identifier": `https://fhir.nhs.uk/Id/nhs-number|${nhsNumber}`,
+    category: `http://snomed.info/sct|${category}`,
+  });
+
+  const res = http.post(
+    `https://${__ENV.HOST}/consumer/DocumentReference/_search`,
+    body,
+    {
+      headers: getHeaders(),
+    }
+  );
+  checkResponse(res);
+}
diff --git a/tests/performance/consumer/soak.js b/tests/performance/consumer/soak.js
index fad1af82d..34495d153 100644
--- a/tests/performance/consumer/soak.js
+++ b/tests/performance/consumer/soak.js
@@ -44,6 +44,18 @@ export const options = {
         { target: 0, duration: "1m" },
       ],
     },
+    searchDocumentReferenceByCategory: {
+      exec: "searchDocumentReferenceByCategory",
+      executor: "ramping-arrival-rate",
+      startRate: 0,
+      timeUnit: "1s",
+      preAllocatedVUs: 5,
+      stages: [
+        { target: 10, duration: "5m" },
+        { target: 10, duration: "30m" },
+        { target: 0, duration: "1m" },
+      ],
+    },
     searchPostDocumentReference: {
       exec: "searchPostDocumentReference",
       executor: "ramping-arrival-rate",
@@ -56,5 +68,17 @@ export const options = {
         { target: 0, duration: "1m" },
       ],
     },
+    searchPostDocumentReferenceByCategory: {
+      exec: "searchPostDocumentReferenceByCategory",
+      executor: "ramping-arrival-rate",
+      startRate: 0,
+      timeUnit: "1s",
+      preAllocatedVUs: 5,
+      stages: [
+        { target: 10, duration: "5m" },
+        { target: 10, duration: "30m" },
+        { target: 0, duration: "1m" },
+      ],
+    },
   },
 };
diff --git a/tests/performance/consumer/stress.js b/tests/performance/consumer/stress.js
index 5df6e69e4..1ee5a7df0 100644
--- a/tests/performance/consumer/stress.js
+++ b/tests/performance/consumer/stress.js
@@ -35,6 +35,15 @@ export const options = {
         { target: 10, duration: "1m" },
       ],
     },
+    searchDocumentReferenceByCategory: {
+      exec: "searchDocumentReferenceByCategory",
+      executor: "ramping-vus",
+      startVUs: 1,
+      stages: [
+        { target: 10, duration: "30s" },
+        { target: 10, duration: "1m" },
+      ],
+    },
     searchPostDocumentReference: {
       exec: "searchPostDocumentReference",
       executor: "ramping-vus",
@@ -44,5 +53,14 @@ export const options = {
         { target: 10, duration: "1m" },
       ],
     },
+    searchPostDocumentReferenceByCategory: {
+      exec: "searchPostDocumentReferenceByCategory",
+      executor: "ramping-vus",
+      startVUs: 1,
+      stages: [
+        { target: 10, duration: "30s" },
+        { target: 10, duration: "1m" },
+      ],
+    },
   },
 };
diff --git a/tests/performance/process_results.py b/tests/performance/process_results.py
index e8a1a8d08..440f65da6 100644
--- a/tests/performance/process_results.py
+++ b/tests/performance/process_results.py
@@ -80,7 +80,7 @@ def _create_response_count_figure(data: dict, title: str):
                 fig_labels.add(f"Failure - Status Code {failure.status}")
 
     for index, scenario in enumerate(data.keys()):
-        axes = fig.add_subplot(2, 2, index + 1)
+        axes = fig.add_subplot(3, 3, index + 1)
         scenario_data = data[scenario]
 
         timestamps = []
@@ -149,7 +149,7 @@ def _create_response_time_figure(data: dict, title: str):
     fig.suptitle(title)
 
     for index, scenario in enumerate(data.keys()):
-        axes = fig.add_subplot(2, 2, index + 1)
+        axes = fig.add_subplot(3, 3, index + 1)
         scenario_data = data[scenario]
 
         timestamps = []
diff --git a/tests/utilities/api_clients.py b/tests/utilities/api_clients.py
index 3a3225135..1d06bf2a8 100644
--- a/tests/utilities/api_clients.py
+++ b/tests/utilities/api_clients.py
@@ -3,7 +3,7 @@
 import requests
 from pydantic import BaseModel
 
-from nrlf.core.constants import PointerTypes
+from nrlf.core.constants import Categories, PointerTypes
 from nrlf.core.model import ConnectionMetadata
 
 
@@ -80,6 +80,7 @@ def search(
         nhs_number: str | None = None,
         custodian: str | None = None,
         pointer_type: PointerTypes | None = None,
+        category: Categories | None = None,
         extra_params: dict[str, str] | None = None,
     ):
         params = {**(extra_params or {})}
@@ -100,6 +101,12 @@ def search(
             else:
                 params["type"] = f"http://snomed.info/sct|{pointer_type}"
 
+        if category:
+            if "|" in category:
+                params["category"] = category
+            else:
+                params["category"] = f"http://snomed.info/sct|{category}"
+
         return requests.get(
             f"{self.api_url}/DocumentReference",
             params=params,
@@ -112,6 +119,7 @@ def search_post(
         nhs_number: str | None = None,
         custodian: str | None = None,
         pointer_type: PointerTypes | None = None,
+        category: Categories | None = None,
         extra_fields: dict[str, str] | None = None,
     ):
         body = {**(extra_fields or {})}
@@ -132,6 +140,12 @@ def search_post(
             else:
                 body["type"] = f"http://snomed.info/sct|{pointer_type}"
 
+        if category:
+            if "|" in category:
+                body["category"] = category
+            else:
+                body["category"] = f"http://snomed.info/sct|{category}"
+
         return requests.post(
             f"{self.api_url}/DocumentReference/_search",
             json=body,