test null-value for a list item

Hi

I got a List with an item of DBNull value. I want to test that item is null or not.

if row[1] = “” then

do something

end

Now I got an error everytime I access to that item it got the erro: " Incompatible types ‘DBNull’ and ‘Text Value’ “”

How do I test null-value for a list item ?

Thanks