WASHINGTON, May 20, 2010 -- When Valerie Neumann woke up dazed and physically bruised the morning after her 21st birthday, the awful reality began to sink in that she had been raped. Neumann then made the difficult decision many sexual assault victims make -- to submit to the ordeal of a rape kit at her local hospital.

Testifying before a House panel today, Neumann described how for six hours, a specially trained nurse fleeced her body, pulling hairs, swabbing her thighs and vagina, and taking pictures of bruises and scratch marks on her back. The nurse placed the evidence in a series of sterile envelopes and sent the kit to law enforcement for DNA testing.

"Although I just wanted to pretend nothing happened, I knew what I needed to do," Neumann told the House panel. "It was very hard to go through. My only consolation was that this exam could be used to put my rapist behind bars."

But three years, five months and four days later, Neumann's kit remains untouched and her rapist uncharged after prosecutors told her they didn't have the funds or enough of a legal case to justify having her rape kit tested.

"I used to believe in our justice system," Neumann said. "But after my experience … I can honestly say that if I were raped again, I don't know that I would choose to go to the hospital and be put through a rape kit again."

Today, advocates for sexual assault victims called Neumann's testimony alarming and indicative of fallout from the broader national rape kit testing backlog. They pressed federal lawmakers to enact legislation to help fix the problem.

Neumann's untested rape kit is one of an estimated 180,000 kits completed each year whose potential evidence, which could validate a woman's claims, identify an attacker or exonerate a suspect, loiters on shelves and in warehouses.

"I get a lot of fan mail that says I wish the detective who handled my case was like you," said actress Mariska Hargitay, whose character on "Law & Order" takes on horrific sex crimes.

Hargitay, who has become an advocate for victims of domestic violence and also testified today, said she's received thousands of letters from rape victims about how isolated they feel after completed rape kits and police reports appear to fall on deaf ears.

"Yes, sexual assault is difficult to talk about. … But lives are ruined because of it. If New York City can do what it's done -- get rid of a backlog -- then we can do it elsewhere," said Hargitay.

Feds Help Fund Testing of Rape Kits

New York City, which had a 16,000 rape kit testing backlog more than a decade ago, has kept up to date on all completed rape kits, providing results within 30 to 60 days, according to a report from Human Rights Watch, which tracks the problem.

Los Angeles, another focal area in the backlog debate, has more than 2,000 rape kits in the pipeline awaiting testing, and struggles to complete results within a year after a request is made.

Nationwide, crime labs saw their DNA testing backlog double from the beginning to the end of 2005, the most recent year for which data is available, according to a 2008 report by the Census of Publicly Funded Crime Laboratories.

Experts said testing centers would need to increase their staffs by 73 percent to meet demand. Some law enforcement officials said they don't have the funds or testing infrastructure to meet demand.

"Because of limited capacities, laboratories are forced to prioritize their cases based upon court dates and whether or not a suspect has been identified," said Christian Hassell, assistant director of the FBI laboratory division. "This oftentimes leaves those cases for which there are no suspects ... unanalyzed in evidence or laboratory storage."

It costs between $900 and $1,000 to process and test a rape kit, according to Jeffrey Boschwitz, president of Orchid Cellmark, one of the largest providers of DNA testing.

The federal government helps cities and states foot the bill through grants to local law enforcement agencies through the Debbie Smith Act, but it does not require states to report or enforce efforts to prevent a backlog of rape kit testing. Some of the funds have also gone unspent, because the law stipulates they cannot be used to hire staff.

Lawmakers pledged today to enact revisions to the law.

"We don't know how many Valerie Neumans there are," said Rep. Anthony Weiner, D-N.Y. "If you [states] want to get the help of the federal government to do law enforcement, then you have to come clean about the situation."

Weiner has proposed a law that would require grant recipients to collect DNA samples from all convicted felons in prisons and meet benchmarks for clearing rape kit backlogs. Rep. Carolyn Maloney, D-N.Y., has introduced separate, similar legislation.

Rape Kits Can Provide the Evidence Juries Expect

Experts said the rape kit backlog could be exacerbated by the attitudes of local law enforcement toward sexual assault crimes.

"Half the cops don't even treat the [rape] kits seriously," said Rep. John Conyers, D-Mich..

Prosecutor Kym Worthy of Wayne County, Michigan, said that when "we discovered the problem last September, I wrote a letter to the Chief of Police. He ignored me...for six months."

In her locality, Worthy said there are more than 12,000 unprocessed kits, and that the numbers are climbing. She said some of "these rape kits in the city of Detroit are over 10 years old, so they're victimized again."

But studies show that rape kits are effective in prosecuting crimes.

"Studies have shown that when a rape kit is collected, tested and contains offender DNA, it is significantly more likely that the case will be prosecuted than in cases where no rape kit is collected," said Rep. Bobby Scott, D-Va.

"Without forensic evidence, juries question the case, they question the prosecution, even though it may exist. Juries never understand [in cases] where a rape kit has been performed, why it's not in the courtroom," said Rep. Ted Poe, R-Texas. More tests will cost more money, he said, "but so what."

ABC News' Tom Shine contributed to this report.