Very few places will accept titers for rabies. I have only heard of one county in the US accepting these. The rabies comnedium (sp?) Specifically states that rabies titers can't be used.
That said, many vets will write a letter of exemption (if allowed in your county) if the titers show a protected level. In the US, Kansas state is the only one that rins them, though I send my bloodwork to Jean Dodds lab. And she send it out.