Blood tests for performance-enhancing drugs will be conducted at next year's Summer Olympics in Sydney, but the tests will be mandatory and subject to punishment only if researchers show in the coming months that the current blood tests are reliable and will stand up in court, the International Olympic Committee announced today.

Researchers soon will begin testing the validity of recently devised blood tests that are intended to detect erythropoietin (EPO) and human growth hormone (hGH). The IOC, which has been criticized for a lax attitude with regard to drugs in sports, voted today at an executive board meeting to fund the validation tests with a $2 million pledge.

EPO and hGH are performance-enhancing drugs believed to be popular among athletes and undetectable by the current method of testing urine. Donald Catlin, the head of the IOC-accredited laboratory at UCLA, said today by phone that two new methods of testing blood for the presence of EPO and hGH seem to be "very solid." Neither method has been employed at any athletic event.

"The basic research has been completed," said Catlin, who will be part of the validation testing team. "The data I have seen, the results of the growth hormone and EPO testing, are very promising. That doesn't mean the test will be applied at the Olympics. But we're far, far along from three years ago, when we had nothing to even look at."

It was a $1.5 million pledge by the IOC in 1996--bolstered by another $1.5 million from the European Union--that led to the development of the prospective hGH test by London researcher Peter Sonksen. Several research teams have been working on EPO tests. The EPO testing conducted by the world cycling federation is considered unacceptable for the Olympic Games because that test cannot conclusively determine whether EPO is present in the blood.

As athletes have prepared for the world track and field championships here this week, many have called for the adoption of blood testing as a more reliable alternative than testing urine. Indeed, lawyers have challenged urine test positives with some success in recent years.

Catlin and other scientists will study the proposed blood testing procedures using subjects of both sexes, various nationalities and a wide range of ages. Such a data bank is required for any test to stand up to the inevitable legal scrutiny. So far, most of the validation of the two tests has been performed on Caucasian males.

"Whether the tests will be ready, no one can tell," said IOC executive board member Jacques Rogge. "The minimum we can do is start the search. . . . We need thousands and thousands of samples. You need to validate the test on athletes of different ages and other different conditions."