More than 30 states have laws barring doctors from heeding a call by U.S. health officials to routinely test Americans for the AIDS virus, researchers report.

And states don't seem to be in any rush to change that. None have chosen to remove all barriers since the Centers for Disease Control and Prevention announced new testing guidelines last year, the researchers said in a new study Tuesday.

"I think if they were going to change, they would have done so by now," said Lawrence Gostin, a public health law expert at Georgetown University. He was not involved in the research but agreed with its findings.

But CDC officials disagreed. They cited more than a half-dozen states that have made some kind of law change to simplify HIV testing. Other changes appear to be pending in California and other states, they said.

"I don't think it's a done deal," said Dr. Bernard Branson in CDC's HIV and AIDS prevention division.

The agency's recommendation that all teens and adults under age 65 be tested for HIV when they visit doctor's offices, emergency rooms and other health care centers was hailed by some HIV patient advocates and health policy experts. Supporters said the guidelines could help end the stigma of HIV testing and lead to needed care for an estimated 250,000 Americans who don't yet know they have the disease.

CDC officials said they believed the guidelines would make testing simpler by sparing primary care doctors from having to counsel patients before the test and from getting specific consent to test for HIV. They acknowledged, however, that some state laws might pose an obstacle.

The new study, released Tuesday in the online journal PLoS One, provides new information about the extent of state legal barriers.

The researchers used legal databases to search state laws and look for recent amendments. Their results were current through July. They did not count proposed legislation.

They found that 33 states require informed consent for an HIV test. And 24 states require disclosure of information about the testing and disease, either in pretest counseling or in a consent process.

Both requirements are barriers to the CDC guidelines as currently written, said Leslie Wolf, an associate professor of law at Georgia State University who is the study's lead author.

They found only two states — Rhode Island and Illinois — that took action with the stated intent of trying to better comply with the CDC recommendations. But both states left some form of informed consent or pre-test counseling provision in place, Wolf said.

It's unlikely there will be much additional legislation, now that the news splash about the new guidelines has ended, Gostin said.

"The political impetus was then, and they're on to other things," Gostin said of state legislators.

The CDC doesn't know how many states have some form of legal barrier, partly because laws are subject to multiple interpretations, Branson said.

"It depends how you classify 'barriers.' I can't comment specifically on this study and how they came to their conclusions," he said.

He listed seven states that he said recently modified their informed consent laws in a way that better conforms with CDC recommendations — Illinois, Iowa, Indiana, Louisiana, Maine, New Hampshire and New Mexico.

California's legislature passed such a bill last month, and that state will make eight if Gov. Arnold Schwarzenegger signs it, Branson said.

Branson said there is no national data yet to indicate what impact the CDC guidelines have had.