diff --git a/lib/cartodb/monitoring/health_check.js b/lib/cartodb/monitoring/health_check.js
index 873cd19d..f925c616 100644
--- a/lib/cartodb/monitoring/health_check.js
+++ b/lib/cartodb/monitoring/health_check.js
@@ -40,7 +40,7 @@ HealthCheck.prototype.check = function(config, callback) {
                 ok: false
             }
         };
-    mapnikXmlParams = config;
+    var mapnikXmlParams = config;
 
     Step(
         function getDBParams() {