Lyudmila Blonska of Ukraine is under investigation for a positive doping test and could be stripped of her silver medal in the Olympic heptathlon and banned for life.

The International Olympic Committee said Wednesday it has opened a disciplinary procedure into Blonska, who finished second behind fellow Ukrainian Nataliia Dobrynska last Saturday.

The IOC disciplinary commission and executive board are expected to rule on the case Thursday, and if the test is confirmed, Blonska would become a repeat offender and kicked out of the sport forever.

The 30-year-old Ukrainian served a doping suspension for the steroid Stanozolol between 2003 and 2005.

An official close to the investigation said Blonska had a positive A test for an anobolic steroid. The official spoke on condition of anonymity because the probe was still ongoing.

If the second sample proves positive Thursday, "she will be suspended for life," Lamine Diack, the president of the International Association of Athletics Federations, said in an interview. "Over and done with. And we go on."

The announcement came only hours ahead of Usain Bolt's attempt to clinch a 100-200 sprint double at the Bird's Nest, one of the highlights of the track program.

Diack insisted that Bolt's performance and the three world records set so far on the track would outshine any positive tests.

"This will not spoil the games. It will spoil nothing. If Blonska testing positive would ruin the games, that would kill us," Diack said.

"These things happen. There are 2000 athletes here," he added. "It is not because Blonska is doped that we scrap Bolt. That would kill us."

Diack told reporters earlier he didn't want to go into the debate about the merits of athletes returning from anti-doping violations and competing at the Olympics.

Despite being banned for 12 months for missing three out-of-competition doping tests between October 2005 and July 2006, Christine Ohuruogu won the 400 meters on Tuesday after a legal battle to get her on the British team which wanted to ban her.

Diack said Ohuruogu wasn't the only one, and mentioned Hungarian discus thrower Robert Fazekas, who finished sixth in Tuesday's final after he was stripped of the 2004 title at the Athens Games.

"It may well be we will take measures. The IOC took the measures with the Olympic Games, we could also do similar things and take out sanctions with regard to the world championships," he said.

Diack said he had been notified of the positive result by Gabriel Dolle, the director of the IAAF's medical and anti-doping department.

Blonska is also competing in the long jump and was third in qualifying ahead of Friday's final. Her place in that event is now in jeopardy.

The third-place finisher in the heptathlon was American Hyleas Fountain, who would be bumped up to the silver if Blonska is disqualified. Russia's Tatiana Chernova would move up from fourth to the bronze.

Blonska won the silver medal in the heptathlon at last year's world championships in Osaka, Japan, and took gold in the pentathlon at the 2006 world indoors in Moscow.

British athlete Kelly Sotherton, who finished fifth in the Olympic heptathlon, complained publicly for months that Blonska shouldn't be allowed to compete in Beijing because of her doping past.

"I'm pleased her teammate beat her," Sotherton said last Saturday. "That makes it bittersweet. I'd have been really upset if she'd won gold. The penalty you should pay if you take drugs is not to compete at the Olympics."

Four athletes have been disqualified and kicked out of the games so far for positive drug tests — Greek hurdler Fani Halkia, North Korean shooter Kim Jong Su, Spanish cyclist Isabel Moreno and Vietnamese gymnast Thi Ngan Thuong Do.

Earlier Wednesday, IOC spokeswoman Giselle Davies said a total of 4,133 tests had been conducted so far, including more than 3,290 urine controls and 840 blood screenings.

By the end of the games Sunday, the IOC will have carried out between 4,500 to 5,000 doping tests in Beijing, up from 3,600 in Athens four years ago.

Davies said 39 athletes had been caught ahead of the games in testing by international sports federations and anti-doping organizations.

"The IOC was very clear in the lead-up we would work in concert with all the anti-doping bodies," she said. "We feel the deterrent effect plays a part in what we see here. The athletes know the IOC means business."

Because of the spate of high-profile doping scandals in recent years, there is intense media and public interest in the test results from marquee Olympic events, especially the men's 100 meters.

Davies said she didn't know whether all tests had come back clean from Saturday's final in which Bolt won the gold medal in a world record time of 9.69 seconds.

Davies said she wasn't privy to results from specific tests or events, noting 300 to 350 samples are being analyzed each day.

Normally, it takes 24 hours for a negative test to be confirmed, 48 hours for positive tests for steroids, and 72 hours for positive results for the blood-booster EPO.