VBA code to check if the Date field is NULL (Blank)

Hi Guys

I am trying to write VbA code that will check if the Date field value is NULL but its not recognising it and going to Else part.

if rs.fields(p).value=null then
msgbox "date is null"
else
msgbox "date is not null"
end if

even if I change it to as below then again it doesn't work.

if isnull(rs.fields(p).value)

Any help will be much appreciated.
Thanks