CHICAGO (AP) -- The U.S. Anti-Doping Agency has launched the opening phase of a voluntary pilot program it hopes will improve the accuracy of doping tests.
The anti-doping agency will profile the body chemistry of 12 participating athletes using a series of blood and urine tests, and those measurements will be used as a baseline for subsequent tests.
The program was described to The Associated Press by two people familiar with it, but who did not want to be identified because final details are still being worked out.
At a news conference Wednesday, track athletes Bryan Clay and Allyson Felix each announced they were part of the project, called "Project Believe."
Cyclist Kristin Armstrong had previously told AP she was asked to join a USADA pilot program.
"I know for me, anytime I get an opportunity to let someone know I'm clean, I take it," said Clay, a decathlete. "USADA picked a few athletes that they're going to test a whole lot. The goal is to prove we're clean instead of dirty, and we want to be part of that."
Clay said he first was tested under the auspices of the program before the world indoor championships last month.
"I'm anxious to let people know 'Hey, look, I'm clean. I'm the athlete you should be behind,'" he said. "I'm going to do it right so these things don't happen."
The program is being set up to augment the current system after the Beijing Olympics, a quest USADA has been charged with by the U.S. Olympic Committee, which established the independent agency in 2000.
One person familiar with the program said a positive test produced under this program could, in theory, stand up as a true positive in the current anti-doping system; the person was not specific about whether such a test might be enough to specifically disqualify a participant from the Beijing Olympics.
USADA's CEO, Travis Tygart, acknowledged a "longitudinal testing program" is in the works and said he expects a more formal announcement in the near future.
But under a series of questions about doping at a USOC news conference, Clay and Felix revealed the program. Felix said it requires her to be tested twice a week, giving a total of five vials of blood, and repeat the regimen over a "period of time."
"Whatever I can do to prove that I'm clean, I'll do it, no matter what time I have to wake up, where I have to drive," Felix said.
Pressed about more details of the program, Felix said "I think that actually has not been released yet, so I'm going to wait to talk about it."
"Anything that's with anti-doping, definitely I can't say enough about it," she said. "I'll do whatever possible to prove I am a clean athlete."
The program will be similar to one the international cycling federation is trying to introduce - a so-called "longitudinal passport" program that many anti-doping experts believe can be more effective in detecting drug cheats than the current system.
A person familiar with the program told AP there will be mechanisms in the program to add to the original list of 12 volunteers. That person also told the AP the program would exceed what the UCI program attempts because it will combine blood and urine testing; the UCI program is only with blood.
The passport system would measure an athlete's baseline numbers against numbers gleaned from later tests, in or out of competition, and if the numbers varied by enough, it could be considered a positive test.
These tests wouldn't necessarily look for specific substances, but could detect changes in body chemistry that would indicate use.
Don Catlin, an anti-doping expert and one of the foremost authorities on longitudinal testing, said the theory behind the USADA project is solid, a "much more powerful technique than simply taking one slice in time."
"It's no surprise that good athletes, clean athletes, will jump up and down for this thing," Catlin said. "That's great. It's about time they started doing something. So now, it's 'OK, it's here, it's now.' And I'm sure there are going to be issues about how to get on the program."
This type of system could someday replace the current anti-doping system, which establishes arbitrary limits for a large number of controlled substances. It's believed athletes can manipulate the system so they can dope but remain under the threshold where they'd get caught.
"New approaches and resources are continually being introduced in the fight against doping in sport," USOC spokesman Darryl Seibel said.