diff --git a/SciXPipelineUtils/scix_id.py b/SciXPipelineUtils/scix_id.py
index a7ccff8..dffa5be 100644
--- a/SciXPipelineUtils/scix_id.py
+++ b/SciXPipelineUtils/scix_id.py
@@ -209,14 +209,21 @@ def generate_bib_data_hash(hash_data, strip_characters=True, user_fields=None):
         "copyright",
     ]
 
-    if user_fields:
-        unique_fields = user_fields
+    hash_data_fields = list(hash_data.keys())
 
-    for field in unique_fields:
-        try:
-            hash_data.pop(field)
-        except Exception:
-            continue
+    if user_fields:
+        for field in hash_data_fields:
+            if field not in user_fields:
+                try:
+                    hash_data.pop(field)
+                except Exception:
+                    continue
+    else:
+        for field in unique_fields:
+            try:
+                hash_data.pop(field)
+            except Exception:
+                continue
 
     if strip_characters and hash_data.get("abs"):
         hash_data["abs"][0] = re.sub("<[^<]+?>", "", hash_data.get("abs")[0])
diff --git a/tests/test_scix_id.py b/tests/test_scix_id.py
index 3b72cfb..ee23e5b 100644
--- a/tests/test_scix_id.py
+++ b/tests/test_scix_id.py
@@ -81,7 +81,7 @@ def test_generate_scix_id_user_fields(self):
         user_fields = ["id"]
         scix_id = scixid.generate_scix_id(test_bib_data, user_fields=user_fields)
         scix_id_2 = scixid.generate_scix_id(test_bib_data)
-        self.assertEqual(scix_id, "3YG1-418S-68AF")
+        self.assertEqual(scix_id, "44GP-FCA0-SEWD")
         self.assertNotEqual(scix_id, scix_id_2)
 
     def test_generate_scix_id_special_characters_true(self):