Nearly everyone aged from 13 to 64 would be screened under the new proposals issued by the U.S. Centers for Disease Control and Prevention. Pregnant women would get extra screening to help ensure they do not pass the virus on to their baby.

The human immunodeficiency virus that causes AIDS infects more than 1 million people in the United States and the CDC estimates that 40,000 people become newly infected every year. But many do not know it because HIV causes mild symptoms at first, quietly destroying the immune system over time.

"We urgently need new approaches to reach the quarter-million Americans with HIV who do not realize they are infected," said CDC Director Dr. Julie Gerberding.

"People with HIV have a right to know that they are infected so they can seek treatment and take steps to protect themselves and their partners."

AIDS is incurable, and infected people risk passing it to sex partners, to their babies and in blood or shared needles. A cocktail of drugs, now available in once- or twice-a-day single pills, can keep patients healthy, and patients who use condoms reduce their risk of passing it along.

Current guidelines call for people considered at high risk to get tested for the virus. But Dr. Bernard Branson, who is in charge of laboratory diagnostics at CDC, said doctors were not always good at guessing who might be at high risk.

And people are often reluctant to admit to high-risk behavior, such as drug use or anal sex, even to their doctors.

"Our goal is to ensure that everyone who receives medical care also has the opportunity to learn if they are infected with HIV," said Dr. Kevin Fenton, Director of CDC's National Center for HIV, STD and TB Prevention.

MAKING TESTING EASIER

"These new recommendations will make routine HIV screening feasible in busy medical settings where it previously was impractical. Making the HIV test a normal part of care for all Americans is also an important step toward removing the stigma still associated with testing."

Branson said regularly testing teenagers would help make them start thinking about AIDS early, before they begin having sex.

"Our data show that too many young people acquire HIV infection at relatively young ages, oftentimes with very early partners," Branson told reporters.

The CDC estimates that between 16 million and 22 million HIV tests are conducted in the United States every year.

AIDS experts welcomed the new recommendations, with some cautions.

The American Academy of HIV Medicine said it was important to allow patients to opt out of the test easily, and to make sure they knew what it meant.

"We fear that the CDC's recommendations will lead to clinicians simply telling the patient he or she will receive a test," the group's Dr. Michelle Roland said in a statement.

Dr. Donna Futterman, head of the Adolescent AIDS Program at Montefiore Medical Center in the Bronx in New York, said one study showed that 80 percent of young men who had sex with other men did not know when they were HIV infected.

"We are hoping that this new call for universal testing will reduce some of the stigma," Futterman said in a telephone interview. "We don't have a medical cure for HIV, we don't have a vaccine for HIV, but we certainly can find and link to care all who have it."