Value is zero and setting my description to NULL

The value is 0 and if not find something in the code, it is setting the @STATUS_DESCRIPTION to null, i want to include the value zero as it could be zero or a numeric.
How do i change the line to accept this, there could be multiple values that i am just joining together in a status

DECLARE @SOURCE_CUST_TERMS_KEY int, @TARGET_CUST_TERMS_KEY int, @FOUND_CUST_TERMS_KEY INT, @STATUS_DESCRIPTION NVARCHAR(MAX), @STATUS_FL VARCHAR(1), @CUST_TERMS_KEY INT

			SELECT  @FOUND_CUST_TERMS_KEY = 0
			SELECT  @TARGET_CUST_TERMS_KEY = 0
			SELECT  @SOURCE_CUST_TERMS_KEY = 0
			SELECT  @CUST_TERMS_KEY = 1

                 ---Is doing some data reads here etc, and if result is zero or a numeric want to return for the user

			IF @TARGET_CUST_TERMS_KEY = 0
				BEGIN
					SELECT @STATUS_DESCRIPTION = @STATUS_DESCRIPTION  + '5-CUST_TERMS_KEY'  + ':' +  CONVERT(nvarchar(20),@CUST_TERMS_KEY) + ' Is not found   '
					SELECT @STATUS_FL = 'N'
					SELECT @CUST_TERMS_KEY = @TARGET_CUST_TERMS_KEY
				END

				PRINT 'CHECK ' + @STATUS_DESCRIPTION

hi

not sure what you mean !!

but

ISNULL(@STATUS_DESCRIPTION,0)

Thanks let me try that.