DALLAS (April 12, 2005) -- The NFL and its players have agreed to follow stricter standards for testosterone levels for the start of next season.

The upgrade, which required the approval of the NFL Players Association, had been expected to be adopted, but not until next month, when the NFL and the union hold their annual discussions about revising the drug program. However, commissioner Paul Tagliabue said that the union had approved the new standards, which continue its practice of using the guidelines set by the Olympics.

"I know we've reached some preliminary agreements with the players last week and we'll probably finalize them next week," Tagliabue said during a speech as part of the SMU Lecture Series. Cowboys owner Jerry Jones and Kansas City Chiefs owner Lamar Hunt were among the attendees.

The NFL's program -- which includes random testing and suspensions for first-time failures -- has been widely credited as being among the toughest in professional sports.

Last week, the NFL submitted documents to a Congressional subcommittee which investigated steroids in baseball and is continuing with scrutiny in other sports. CBS' "Sixty Minutes" reported two weeks ago that three Carolina Panthers players had steroid prescriptions filled by a South Carolina doctor now under investigation by federal authorities.

Under the previous guideline used by the International Olympic Committee and the NFL, a ratio above 6:1 of testosterone to epitestosterone, another natural hormone, was considered a failed test. Now it's 4:1.

The most likely natural ratio of testosterone to epitestosterone in humans is 1:1.

"We try to stay as much ahead of the curve as we can," Gene Upshaw, the executive director of the NFL Players Association, said in a telephone interview. "We support trying to get cheaters off the field any way we can. This is another example of that."

The IOC made its change after new equipment became available. The NFL hopes to keep pace in the fight against steroids and other performance-enhancing substances, having announced last month the formation of a new drug-testing laboratory in conjunction with the United States Anti-Doping Agency.

More modifications, such as adding items to the list of banned substances, are expected at the upcoming meeting. The annual review usually doesn't draw much attention, but Congress usually doesn't subpoena baseball players, either.

Another issue Tagliabue is facing involves a new collective bargaining agreement. In addition to getting players and owners to work things out, he's trying to unite the owners' stance. He's called a special session next week in Atlanta to continue talks held last month at the league's annual meetings.

"With some luck and ideas, we'll get it done," he said. "But we're not there yet."