An Australian researcher who helped develop a revolutionary blood-doping test said yesterday that more sophisticated versions are on the way that could nab all drug cheats within two years.

　　Michael Ashenden was one of the team at Sydney's Royal Prince Alfred Hospital which helped develop the blood doping test that caused American cyclist and time trial gold medalist Tyler Hamilton's positive test at the Athens Games.

　　On Thursday, the International Olympic Committee said it had dropped its investigation into Hamilton's initial positive test because the Athens lab mishandled his backup blood sample.

　　That hasn't diminished Ashenden's optimism that drug cheats could be more easily identified by a series of new tests that will be developed soon.

　　Hamilton, who has declared he is "100 percent innocent," tested positive for signs of an illegal blood transfusion on Augus 19.

　　"I think the most important thing to come out of recent days is that cheats now know that they must stop transfusions or they will be caught," Ashenden said in a telephone interview with The Associated Press. "They know once and for all we mean business. The gloves are off. We have a test to protect clean athletes."

　　He called on Hamilton to give up his Athens gold medal.

　　"I think it's time for Tyler Hamilton to show decency and honor and to respect the Olympic movement," said Ashenden. "He should come clean rather than hide under the skirt of legal advice. He should have the moral courage to do the right thing."

　　Ashenden said a foolproof test for any type of doping is in the works. "We are undertaking research that has the potential to detect all forms of doping, and if all goes to plan, hope to have it ready in that (two-year) time frame," said Ashenden.

　　Hamilton's positive finding could not be confirmed because of a shortage of intact red blood cells in his second sample, the IOC said. An athlete is considered guilty of doping only when both samples from a drug test come back positive.

　　As a result, the IOC said it "would not be pursuing sanctions regarding this matter."

　　IOC medical commission chairman Arne Ljungqvist said the Athens lab erred by deep-freezing Hamilton's second specimen - known as the B sample - rather than simply refrigerating it. As a result, the blood cells deteriorated and the B sample could not be analyzed, he said.

　　Ashenden cautioned athletes who take illegal substances that even though the foolproof test has not been developed, it will catch them - even eight years from now.

　　"Our current test relies on intact blood red cells, and if you freeze the sample, you are going to have problems," Ashenden said, referring to the botched second Hamilton sample from Athens.

　　"But we are basing the next generation of tests on the other component of blood - serum - and we can freeze that forever. The message that needs to be taken is that we can collect and freeze that serum, come back and reanalyze it.

　　"If the test isn't in place yet, that's immaterial. We can afford to wait for up to eight years to test it."

　　Ross Brown, who along with Margaret Nelson and Ashenden developed the Australian test at Royal Prince Alfred Hospital, said Hamilton will likely be suspended due to samples taken from a Spanish race on September 11.

　　"I don't think we've heard the end of the story," Brown said from Sydney yesterday. "It was unfortunate that human error occurred on the B sample."

　　Ashenden credited the United States Anti-Doping Agency, which provided the funding to allow Royal Prince Alfred to develop the test.

　　And he said the World Anti-Doping Agency provided research funds for his Queensland state-based group - Science and Industry Against Blood Doping Research Consortium.

　　(The Associated Press)