diff --git a/module/VuFind/src/VuFind/ILS/Driver/HorizonXMLAPI.php b/module/VuFind/src/VuFind/ILS/Driver/HorizonXMLAPI.php
index 3420fe540334352f1e4443ce85cec8a8c251f52a..de8d2a3e388b767c341d8641ffb4f000553f1272 100644
--- a/module/VuFind/src/VuFind/ILS/Driver/HorizonXMLAPI.php
+++ b/module/VuFind/src/VuFind/ILS/Driver/HorizonXMLAPI.php
@@ -455,8 +455,8 @@ class HorizonXMLAPI extends Horizon implements \VuFindHttp\HttpServiceAwareInter
             );
 
             // set itemkey only if available and level is not title-level
-            if ($itemData['id'] != '' && $itemData['level'] != 'title') {
-                $params += array("itemkey" => $itemData['id']);
+            if ($itemData['item_id'] != '' && $itemData['level'] != 'title') {
+                $params += array("itemkey" => $itemData['item_id']);
             }
 
             $initResponse = $this->makeRequest($params);