Sept. 5, 2011 -- An adult film performer whose positive HIV test prompted the shutdown of Los Angeles' billion-dollar porn industry last week has been retested and does not have the virus, an industry trade group announced.

"The industry will be abundantly cautious as we try to nail down the reasons for what now appears to have been a false positive result on a previous test," Free Speech Coalition spokeswoman Diane Duke told the Associated Press, adding that production could resume.

HIV tests detect antibodies to the virus in a person's blood. But because they are developed to be especially sensitive, they can sometimes generate a false positive result, according to the World Health Organization. Therefore, positive results must be confirmed by another test method.

Duke declined to release any details about the performer, citing the person's right to medical privacy, the AP reported Saturday.

The HIV scare came less than one month after the Free Speech Coalition launched a new online sexual health database aimed at preventing the spread of sexually transmitted diseases among porn actors through mandatory testing. To be listed in the database -- a requisite for getting work -- porn actors must get tested every 30 days and present a clean bill of health. But critics say routine testing does not prevent STDs from creeping in.

"Testing is not a substitute for condom use, and it never will be," said Michael Weinstein, president of the AIDS Healthcare Foundation in Los Angeles. "No test can detect HIV from the moment of infection. There will always be a window period," which might not reflect recent infection.

The AIDS Healthcare Foundation is pushing for mandatory condom use in the making of adult films -- a move that's met with strong resistance from the industry itself.

"If the market would accept condom-positive movies, that's what we would all be making. The fact is consumers don't want that," Christian Mann, general manger of Evil Angel Productions and unpaid Free Speech Coalition board member, told ABCNews.com when the database launched.

"The market will always trump regulation," said Mann. "If you make it so California-based productions cannot compete in the market, you'll just drive production out of the state."

But Weinstein insists that worker safety should not be optional.

"You can't dangle from a 30-story building from a rope; you have to wear a harness," he said. "The idea that hurting these performers is a matter of freedom of expression is simply wrong."

Porn Industry Database: Is Testing Enough?

The adult entertainment industry has had its share of sexual health scares. In 1998, veteran porn actor Mark Wallice tested HIV-positive after reputedly hiding his positive status for two years and infecting several co-stars. In 2004, Darren James spread the virus to three women, shutting down film production industrywide for a month. And in 2009, a positive HIV test for a performer known only as "Patient Zero" sparked a legal battle between the California Department of Occupational Safety and Health and AIM Medical Associates over performers' rights to medical privacy.

ABCNews.com spoke to several performers who favor mandatory testing over mandatory condom use.

Bobbi Starr, a relative newcomer with five years in the industry, said she wouldn't work with someone with a troubling sexual health history. And Nina Hartley, a veteran porn performer with 27 years in the industry and a degree in nursing, argued that condoms make on-set sex uncomfortable and possibly more dangerous.

"I would say it's different in a civilian population," said Hartley. "But public health is not served by forcing a small group of professionals to use condoms instead of being tested."

The new HIV case brings all these issues to the fore again.

"There really cannot be an argument over the fact that these performers would be far safer if they used condoms," said Weinstein.

The AIDS Healthcare Foundation is lobbying for a measure on L.A.'s June 2012 ballot that would mandate condom use in porn productions that seek city film permits.

The Associated Press contributed to this report.