FRANKFURT (Reuters) - Genetic-testing specialist Qiagen, which has been burdened by weak U.S. demand for two years, aims to return to double-digit percentage sales growth next year, its finance chief told Reuters on Tuesday.

Chief Financial Officer Roland Sackers also said that the maker of a genetic test for the virus that causes cervical cancer aims to increase its margin of earnings before interest and taxes (EBIT) over sales by 0.75 to 1 percentage points in 2012.

(Reporting by Ludwig Burger, Andreas Kroener and Frank Siebelt)