Dim rst As DAO.Recordset
Dim i As Long
Set rst = CurrentDb.OpenRecordset("Select * From Your Table")
While not rst.eof and not rst.bof
For i = 0 To rst.Fields.Count - 1
If IsNull(rst.Fields(i)) Then
Debug.print rst.Fields(i).Name
End If
Next I
rst.MoveNext
Wend