ELKTON, Md. – Starting next year across the country, rape victims too afraid or too ashamed to go to police can undergo an emergency-room forensic rape exam, and the evidence gathered will be kept on file in a sealed envelope in case they decide to press charges.

The new federal requirement that states pay for “Jane Doe rape kits” is aimed at removing one of the biggest obstacles to prosecuting rape cases: Some women are so traumatized they don’t come forward until it is too late to collect hair, semen or other samples.

“Sometimes the issue of actually having to make a report to police can be a barrier to victims, and this will allow that barrier to cease, to allow the victim to think about it before deciding whether to talk to police,” said Carey Goryl, executive director of the International Association of Forensic Nurses.

The practice is already followed at some health clinics, colleges and hospitals around the country and by the state of Massachusetts. But many other jurisdictions refuse to cover the estimated $800 cost of a forensic rape exam unless the victim files a police report.

Beginning in 2009, states will have to pay for Jane Doe rape kits to continue receiving funding under the federal Violence Against Women Act, which provides tax dollars for women’s shelters and law enforcement training. States will decide how many locations will offer anonymous rape exams and how long the evidence should be kept.

Emergency rooms typically use a “rape kit” to collect evidence for use by police and prosecutors. It consists of microscope slides, boxes and plastic bags for storing skin, hair, blood, saliva or semen gathered by a specially trained nurse. The victim’s injuries are also photographed.

What makes a Jane Doe rape kit different is that it is sealed with only a number on the outside of the envelope to identify the victim. Police do not open the envelope unless the victim decides to press charges.

The FBI has recommended such an option since at least 1999.

“The idea is to collect the evidence now, while it’s still there,” said Scott Berkowitz, president of the national Rape, Abuse and Incest National Network.

The new requirement applies only to adult victims. Hospitals and doctors must still report incest or abuse involving children to the police.

In Cecil County, local authorities started offering Jane Doe kits four years ago, after a rape victim recanted. Anne Bean, clinical director for a rape and sexual assault counseling program in Cecil County, said giving women the option of keeping police out of it until they are ready to press charges is crucial.

According to the U.S. Justice Department, 272,350 sexual assaults were reported in 2006. The same survey estimated that only 41 percent of rapes and other sexual assaults are reported to police.

“Many times, you have people who were drunk, maybe doing drugs, maybe they’re underage, and you start talking about the police and they get scared,” Bean said. “So, sometimes it’s not until long after they’re willing to report, at which point of course any physical evidence is gone.”

Massachusetts officials had no immediate figures on how many rape kits were collected anonymously there, or how many were ultimately opened.

In Allegany and Cecil counties in Maryland, evidence is kept at least 90 days. So far, 13 women have submitted anonymous evidence, and none has returned to press charges.

Still, hospital and police officials credit an offer of Jane Doe testing with encouraging a reluctant victim in Cecil County to undergo an exam. During that process, she decided to report the crime, and her attacker was successfully prosecuted.

“Just to let people know this option is out there is good, to say, ‘It’s OK, you don’t have to prosecute if you don’t want to,'” said Kathleen, a rape victim in Pennsylvania who spoke on condition her full name not be used.

Kathleen underwent an exam after being raped in Virginia in 2004, but her rapist was never found or charged. Kathleen said she wasn’t offered anonymous reporting, but she has met rape victims in group therapy who regret not going for an exam.

“They’re embarrassed. They don’t even go get tested for STDs because they’re so embarrassed,” Kathleen said.

At Union Hospital in Elkton, forensic nurse Chris Lenz said Jane Doe testing is not offered unless a medical professional fears the victim will leave without the option.

“Of course we encourage reporting. That’s what we would like. But when they’re adamant they don’t want to report – if we think, ‘She’s going to walk out if she has to go through with this,’ – that’s when we offer it,” Lenz said.