diff --git a/python/obitools3/obidms/_obidmscolumn_qual.pyx b/python/obitools3/obidms/_obidmscolumn_qual.pyx
index a6e4a6b..90d4762 100644
--- a/python/obitools3/obidms/_obidmscolumn_qual.pyx
+++ b/python/obitools3/obidms/_obidmscolumn_qual.pyx
@@ -32,7 +32,7 @@ cdef class OBIDMS_column_qual(OBIDMS_column):
         value = obi_column_get_obiqual_int_with_elt_idx_in_view(self.view.pointer, (self.pointer)[0], line_nb, 0, &value_length)
         if obi_errno > 0 :
             raise IndexError(line_nb)
-        if value == NULL :  # TODO
+        if value == OBIQual_int_NA :
             result = None
         else :
             result = []
@@ -47,7 +47,7 @@ cdef class OBIDMS_column_qual(OBIDMS_column):
         value = obi_column_get_obiqual_char_with_elt_idx_in_view(self.view.pointer, (self.pointer)[0], line_nb, 0)
         if obi_errno > 0 :
             raise IndexError(line_nb)
-        if strcmp(value, OBIQual_char_NA) == 0 :
+        if value == OBIQual_char_NA :
             result = None
         else :
             result = bytes2str(value)
@@ -58,7 +58,7 @@ cdef class OBIDMS_column_qual(OBIDMS_column):
         cdef uint8_t* value_b
         cdef int      value_length
         if value is None :
-            value_b = NULL   # TODO
+            value_b = OBIQual_int_NA
             value_length = 0
         else :
             value_length = len(value)
@@ -80,7 +80,7 @@ cdef class OBIDMS_column_qual(OBIDMS_column):
             raise Exception("Problem setting a value in a column")
 
 
-# TODO OR NOT?
+# TODO
 # cdef class OBIDMS_column_multi_elts_qual(OBIDMS_column_multi_elts):
 # 
 # 
diff --git a/python/obitools3/obidms/_obidmscolumn_seq.pyx b/python/obitools3/obidms/_obidmscolumn_seq.pyx
index 3dc67e9..6f50269 100644
--- a/python/obitools3/obidms/_obidmscolumn_seq.pyx
+++ b/python/obitools3/obidms/_obidmscolumn_seq.pyx
@@ -13,7 +13,6 @@ from ._obidms           cimport OBIView
 from obitools3.utils cimport str2bytes, bytes2str
 
 from libc.stdlib cimport free
-from libc.string cimport strcmp
 
 
 cdef class OBIDMS_column_seq(OBIDMS_column):
@@ -24,7 +23,7 @@ cdef class OBIDMS_column_seq(OBIDMS_column):
         value = obi_column_get_obiseq_with_elt_idx_in_view(self.view.pointer, (self.pointer)[0], line_nb, 0)
         if obi_errno > 0 :
             raise IndexError(line_nb)
-        if strcmp(value, OBISeq_NA) == 0 :
+        if value == OBISeq_NA :
             result = None
         else :
             result = bytes2str(value)
@@ -61,7 +60,7 @@ cdef class OBIDMS_column_multi_elts_seq(OBIDMS_column_multi_elts):
         value = obi_column_get_obiseq_with_elt_name_in_view(self.view.pointer, (self.pointer)[0], line_nb, str2bytes(element_name))
         if obi_errno > 0 :
             raise IndexError(line_nb, element_name)
-        if strcmp(value, OBISeq_NA) == 0 :
+        if value == OBISeq_NA :
             result = None
         else :
             result = bytes2str(value)
@@ -80,7 +79,7 @@ cdef class OBIDMS_column_multi_elts_seq(OBIDMS_column_multi_elts):
             value = obi_column_get_obiseq_with_elt_idx_in_view(self.view.pointer, (self.pointer)[0], line_nb, i)
             if obi_errno > 0 :
                 raise IndexError(line_nb)
-            if strcmp(value, OBISeq_NA) == 0 :
+            if value == OBISeq_NA :
                 value_in_result = None
             else :
                 value_in_result = bytes2str(value)
diff --git a/python/obitools3/obidms/_obidmscolumn_str.pyx b/python/obitools3/obidms/_obidmscolumn_str.pyx
index d3f4b90..0678916 100644
--- a/python/obitools3/obidms/_obidmscolumn_str.pyx
+++ b/python/obitools3/obidms/_obidmscolumn_str.pyx
@@ -9,8 +9,6 @@ from .capi.obitypes     cimport OBIStr_NA, const_char_p
 
 from obitools3.utils cimport str2bytes, bytes2str
 
-from libc.string cimport strcmp
-
 
 cdef class OBIDMS_column_str(OBIDMS_column):
 
@@ -20,7 +18,7 @@ cdef class OBIDMS_column_str(OBIDMS_column):
         value = obi_column_get_obistr_with_elt_idx_in_view(self.view.pointer, (self.pointer)[0], line_nb, 0)
         if obi_errno > 0 :
             raise IndexError(line_nb)
-        if strcmp(value, OBIStr_NA) == 0 :
+        if value == OBIStr_NA :
             result = None
         else :
             result = bytes2str(value)
@@ -45,7 +43,7 @@ cdef class OBIDMS_column_multi_elts_str(OBIDMS_column_multi_elts):
         value = obi_column_get_obistr_with_elt_name_in_view(self.view.pointer, (self.pointer)[0], line_nb, str2bytes(element_name))
         if obi_errno > 0 :
             raise IndexError(line_nb, element_name)
-        if strcmp(value, OBIStr_NA) == 0 :
+        if value == OBIStr_NA :
             result = None
         else :
             result = bytes2str(value)
@@ -64,7 +62,7 @@ cdef class OBIDMS_column_multi_elts_str(OBIDMS_column_multi_elts):
             value = obi_column_get_obistr_with_elt_idx_in_view(self.view.pointer, (self.pointer)[0], line_nb, i)
             if obi_errno > 0 :
                 raise IndexError(line_nb)
-            if strcmp(value, OBIStr_NA) == 0 :
+            if value == OBIStr_NA :
                 value_in_result = None
             else :
                 value_in_result = bytes2str(value)
diff --git a/python/obitools3/obidms/capi/obitypes.pxd b/python/obitools3/obidms/capi/obitypes.pxd
index 6a83a26..d765629 100644
--- a/python/obitools3/obidms/capi/obitypes.pxd
+++ b/python/obitools3/obidms/capi/obitypes.pxd
@@ -1,7 +1,8 @@
 #cython: language_level=3
 
 
-from libc.stdint cimport int32_t, int64_t
+from libc.stdint cimport int32_t, int64_t, uint8_t
+
 from posix.types cimport time_t
 
 
@@ -47,8 +48,8 @@ cdef extern from "obitypes.h" nogil:
     extern obibool_t     OBIBool_NA
     extern const_char_p  OBISeq_NA
     extern const_char_p  OBIStr_NA
-    extern const_char_p  OBIQual_int_NA
     extern const_char_p  OBIQual_char_NA
+    extern uint8_t*      OBIQual_int_NA
 
     const_char_p name_data_type(int data_type)