Prince Alexandre de Merode, chairman of the...

Prince Alexandre de Merode, chairman of the International Olympic Committee’s medical commission, said that a new procedure for testing for banned substances has turned up 50 positives for anabolic steroids from 1,110 samples taken at the Seoul Olympics.

“We are unable to detect the name of the drug that has been used,” de Merode told the New York Times Friday as IOC officials gathered in San Juan, Puerto Rico, for their annual meeting. “But we believe with this system we are able to prove that athletes have taken anabolic steroids.”

The identities of those who tested positive are not known because the documents matching the control numbers of urine samples and the athletes’ names were destroyed after the Games, as is customary.

In Seoul, where all medalists and others picked at random were tested, only 10 athletes tested positive for illegal substances, including Canadian sprinter Ben Johnson, who was stripped of the gold medal after winning the 100-meter dash.

The test that produced the new results was conducted at the University of Cologne in West Germany by Dr. Manfred Donike, a member of the medical commission.

De Merode termed the test “only scientific research, nothing more.”

It is common practice for international laboratories to retain samples collected at competitions and freeze them for later use. It helps officials refine their testing procedures.