diff --git a/application/controllers/api/v1/crm/Prestudent.php b/application/controllers/api/v1/crm/Prestudent.php
index 3bc18849b..5d5ff063b 100644
--- a/application/controllers/api/v1/crm/Prestudent.php
+++ b/application/controllers/api/v1/crm/Prestudent.php
@@ -130,7 +130,7 @@ class Prestudent extends APIv1_Controller
 		$von = $this->get('von');
 		$bis = $this->get('bis');
 
-		if (isset($status_kurzbz))
+		if (isset($status_kurzbz) && isset($von) && isset($bis))
 		{
 			$result = $this->PersonModel->getPersonFromStatus(
 				$status_kurzbz,