diff --git a/imednet/endpoints/records.py b/imednet/endpoints/records.py
index 8c445023..a62cbb26 100644
--- a/imednet/endpoints/records.py
+++ b/imednet/endpoints/records.py
@@ -64,6 +64,18 @@ def _build_headers(self, email_notify: Union[bool, str, None]) -> Dict[str, str]
                 headers[HEADER_EMAIL_NOTIFY] = str(email_notify).lower()
         return headers
 
+    def _prepare_create_request(
+        self,
+        study_key: str,
+        records_data: List[Dict[str, Any]],
+        email_notify: Union[bool, str, None],
+        schema: Optional[SchemaCache],
+    ) -> tuple[str, Dict[str, str]]:
+        self._validate_records_if_schema_present(schema, records_data)
+        headers = self._build_headers(email_notify)
+        path = self._build_path(study_key, self.PATH)
+        return path, headers
+
     def create(
         self,
         study_key: str,
@@ -89,10 +101,9 @@ def create(
         Raises:
             ValueError: If email_notify contains invalid characters
         """
-        self._validate_records_if_schema_present(schema, records_data)
-        headers = self._build_headers(email_notify)
-
-        path = self._build_path(study_key, self.PATH)
+        path, headers = self._prepare_create_request(
+            study_key, records_data, email_notify, schema
+        )
         response = self._client.post(path, json=records_data, headers=headers)
         return Job.from_json(response.json())
 
@@ -124,10 +135,9 @@ async def async_create(
             ValueError: If email_notify contains invalid characters
         """
         client = self._require_async_client()
-        self._validate_records_if_schema_present(schema, records_data)
-        headers = self._build_headers(email_notify)
-
-        path = self._build_path(study_key, self.PATH)
+        path, headers = self._prepare_create_request(
+            study_key, records_data, email_notify, schema
+        )
         response = await client.post(path, json=records_data, headers=headers)
         return Job.from_json(response.json())
 
diff --git a/imednet/endpoints/subjects.py b/imednet/endpoints/subjects.py
index 09975f91..0dd35cec 100644
--- a/imednet/endpoints/subjects.py
+++ b/imednet/endpoints/subjects.py
@@ -17,6 +17,11 @@ class SubjectsEndpoint(ListGetEndpoint[Subject]):
     MODEL = Subject
     _id_param = "subjectKey"
 
+    def _filter_by_site(self, subjects: List[Subject], site_id: str | int) -> List[Subject]:
+        # TUI Logic: Strict string comparison to handle int/str mismatch
+        target_site = str(site_id)
+        return [s for s in subjects if str(s.site_id) == target_site]
+
     def list_by_site(self, study_key: str, site_id: str | int) -> List[Subject]:
         """
         List subjects filtered by a specific site ID.
@@ -24,12 +29,9 @@ def list_by_site(self, study_key: str, site_id: str | int) -> List[Subject]:
         Migrated from TUI logic to core SDK to support filtering.
         """
         all_subjects = self.list(study_key)
-        # TUI Logic: Strict string comparison to handle int/str mismatch
-        target_site = str(site_id)
-        return [s for s in all_subjects if str(s.site_id) == target_site]
+        return self._filter_by_site(all_subjects, site_id)
 
     async def async_list_by_site(self, study_key: str, site_id: str | int) -> List[Subject]:
         """Asynchronously list subjects filtered by a specific site ID."""
         all_subjects = await self.async_list(study_key)
-        target_site = str(site_id)
-        return [s for s in all_subjects if str(s.site_id) == target_site]
+        return self._filter_by_site(all_subjects, site_id)