Check for NULL value (Recordset field)

Hi y'all...

A little question, so just for the weekend... 😊

I've a query that returns 4 fields, the fisrt three always containing data, and the last one an integer, or NULL. If I get the value with <i>rs.Fields.Item(3).Value.ToString();</i> it always contains an integer. The NULL values are always converted to '0'.

How can I check if it is a NULL value?