diff --git a/smash/web/forms/study_subject_forms.py b/smash/web/forms/study_subject_forms.py
index 93debc5b236001b458f1cef28af722f5914d60ea..9efcf8096ebce96ed6a03323fdf1ec9090a38a0f 100644
--- a/smash/web/forms/study_subject_forms.py
+++ b/smash/web/forms/study_subject_forms.py
@@ -1,3 +1,4 @@
+import logging
 import re
 
 from django import forms
@@ -7,6 +8,8 @@ from web.forms.forms import DATETIMEPICKER_DATE_ATTRS, get_worker_from_args
 from web.models import StudySubject, Study, StudyColumns
 from web.models.constants import SCREENING_NUMBER_PREFIXES_FOR_TYPE
 
+logger = logging.getLogger(__name__)
+
 
 class StudySubjectAddForm(ModelForm):
     datetime_contact_reminder = forms.DateTimeField(label="Contact on",
diff --git a/smash/web/tests/forms/test_StudySubjectAddForm.py b/smash/web/tests/forms/test_StudySubjectAddForm.py
index 2b71231dd637a4171325d50c10de614907b154d4..29b4a7b7715b80db243e0a3b30053f1a7f3ba7b7 100644
--- a/smash/web/tests/forms/test_StudySubjectAddForm.py
+++ b/smash/web/tests/forms/test_StudySubjectAddForm.py
@@ -30,9 +30,14 @@ class StudySubjectAddFormTests(LoggedInWithWorkerTestCase):
 
     def test_validation_for_study_without_columns(self):
         form = StudySubjectAddForm(data=self.sample_data, user=self.user, study=create_empty_study())
-        form.is_valid()
         self.assertTrue(form.is_valid())
 
+    def test_validate_nd_number(self):
+        self.sample_data['nd_number'] = 'invalid nd number'
+        form = StudySubjectAddForm(data=self.sample_data, user=self.user, study=self.study)
+        self.assertFalse(form.is_valid())
+        self.assertTrue("nd_number" in form.errors)
+
     def test_invalid(self):
         form_data = self.sample_data
         form_data['screening_number'] = "123"