diff --git a/wp-admin/includes/template.php b/wp-admin/includes/template.php
index ef24902302..982c87337d 100644
--- a/wp-admin/includes/template.php
+++ b/wp-admin/includes/template.php
@@ -1952,7 +1952,7 @@ function compression_test() {
 					}
 				}
 
-				x.open('GET', 'admin-ajax.php?action=wp-compression-test&test='+test+'&'+(new Date()).getTime(), true);
+				x.open('GET', ajaxurl + '?action=wp-compression-test&test='+test+'&'+(new Date()).getTime(), true);
 				x.send('');
 			}
 		},