U.S. HIV testing push brings mixed results.(Main)

Just more than 40 percent of the adult U.S. population has been screened at least once for HIV infection, but a quarter of a million people are infected and do not know it, government researchers said Thursday.

About 10 percent of the population receives an HIV test each year - a figure that has remained stable since 2000 despite efforts to increase testing, according to a report from the federal Centers for Disease Control and Prevention. The release of the data was timed to coincide with the International AIDS Conference being held this week in Mexico City.

About 56,300 Americans become infected with HIV each year and between 1 million and 1.1 million …