diff --git a/labkey/query.py b/labkey/query.py
index 31b6a7c..2a8bdfa 100644
--- a/labkey/query.py
+++ b/labkey/query.py
@@ -348,6 +348,9 @@ class Types:
         BETWEEN = 'between'
         NOT_BETWEEN = 'notbetween'
 
+        IS_BLANK = 'isblank'
+        IS_NOT_BLANK = 'isnonblank'
+
         MEMBER_OF = 'memberof'
 
     def __init__(self, column, value, filter_type=Types.EQUAL):