Public health experts say testing in many parts of the country probably won't get going for a year, maybe longer, because of a complex tangle of state laws and the reluctance of some family doctors.
"I think it's going to be very slow progress," said Lawrence Gostin, a public health law professor at Georgetown University.
When the U.S. Centers for Disease Control and Prevention announced the new guidelines last month, they were widely met with enthusiasm. And they were supposed to take effect right away.
The goal is to prevent the further spread of AIDS and reach an estimated 250,000 Americans who don't realize they have HIV. The CDC is recommending testing for all teens and adults under age 65 when they visit doctor's offices, emergency rooms and other health-care centers.
At least one major doctors group — the 94,000-member American Academy of Family Physicians — has declined to take a position on the CDC's new advice, questioning the cost and whether it's really necessary for everyone.
And even doctors who support the guidelines say it won't be as simple as the CDC had hoped.
The idea was that by offering the test to virtually everyone, primary care doctors would be spared from counseling patients before the test and from obtaining specific consent to test for HIV. But laws in New York and in at least two dozen other states require pretest counseling or have other rules that may make it hard for doctors to follow the CDC advice as written.
"The whole point was to try to reduce the bureaucracy and administrative burden" for doctors giving HIV tests, Gostin said.
"But I don't think state laws will allow that," he said, adding that it may take years for some legislatures to ease current restrictions.
"How challenging this is going to be depends on where (what state) the doctor practices," said Dr. Nancy Nielsen, a Buffalo, N.Y.-based physician who sits on the governing board of the American Medical Association.
And then there's the daunting issue of dealing with a patient who has HIV, which some pediatricians and family doctors have rarely faced.
Many primary care doctors customarily refer a patient with HIV to a specialist better equipped to treat the virus and put the patient in touch with support services. That's expected to continue.
But the primary doctor will be expected to break the initial news of the diagnosis to the patient — a task requiring skills some physicians don't always demonstrate, said Dr. Kimberly Manning, an internist at Atlanta's large public hospital, Grady Memorial.
"It's not like someone's cholesterol being high," she said. With HIV, a physician must be prepared to empathize, educate and guide patients into such steps as notifying intimate contacts, she added.
And there is the issue of cost. A routine blood test for HIV can cost between $3 and $5, some health experts say. New rapid tests, done through finger pricks or oral swabs, cost $15 or more.
Some medical centers have been offering rapid tests for free, thanks to government funding and support from companies like Pennsylvania-based OraSure Technologies Inc., one of at least four companies that sell rapid-result HIV tests in the United States.
The programs have been deemed mostly successful. For example, at George Washington University Hospital in Washington, D.C., 58 percent of 1,000 ER patients offered the HIV test have accepted since a pilot program began last month.
But the money for that effort will end someday, and then paying for the test will become an issue.
Health insurers are considering the CDC guidelines, and some have said they usually pay for services recommended by the CDC. But it's more complicated than that.
For example, coverage for treatment in an ER wouldn't normally include an HIV test, said Dr. Jeremy Brown, research director for the hospital's department of emergency medicine.
To help doctors sort out these and other issues, the CDC, AMA and other groups are meeting Oct. 16 in Atlanta.
CDC officials said they never expected HIV testing to become widespread right away. "There are some elements that take time," said the agency's Dr. Rob Janssen.
Once doctors do offer the tests routinely, most patients are expected to go along, several physicians said.
"If they come with the imprimatur of the CDC ... those things are a pretty easy sell to parents," said Dr. Michael Wasserman, a Metairie, La., pediatrician.
Many adult patients get HIV tests when they sign up for life insurance.
Dr. Michael Baron, a Stone Mountain, Ga., family physician, has already begun following the CDC guidance. When routine blood tests are given, he asks patients to allow HIV testing as well.
Mary Osborne, 59, was in for a check-up. Married for 16 years, she considers HIV infection unlikely, but said OK.
A cousin died from AIDS two years ago, she noted. "It (the test) doesn't bother me at all," she said.