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May 6 (Reuters) - Diagnostic tests maker OraSure Technologies Inc (OSUR.O: Quote, Profile, Research) posted a higher quarterly profit, but cut its outlook for the second quarter and full year citing inventory issues and legal expenses among reasons, sending its shares down 13 percent to their new year-low.

The company said the patent infringement lawsuit by Inverness Medical Innovations IMA.A and Church & Dwight (CHD.N: Quote, Profile, Research) will result in an unexpected increase in legal costs during 2008.

In April, the companies filed a lawsuit alleging that OraSure's OraQuick Advance Rapid HIV-½ Antibody Test infringed their patents.

OraSure said an unanticipated inventory buildup at its over-the-counter cryosurgical distributor in Mexico and a recent change in funding sources for the purchase of OraQuick HIV tests in Africa were hurting its business.

OraSure shares fell 87 cents to a new year-low of $5.70 in after-hours trading.

A number of retailers in Mexico had accumulated an inventory level based on in-season demand that was not required over the winter months and returned the products later, Ronald Spair, chief financial officer, said on a conference call with analysts.

LOWER U.S. SALES

OraSure said it is experiencing lower-than-expected growth for OraQuick Advance product sales in the U.S. hospital market and the slowing economy continues to impact hiring and workplace drug testing.