WIMBLEDON, England ? Venus Williams won’t open her home for surprise drug testers. Jennifer Capriati says random testing is an “invasion.”

Despite objections from two of the sport’s biggest stars, the women’s tennis tour said on Tuesday it will introduce out-of-competition testing this year for performance-enhancing substances.

The sport’s international body, meanwhile, said it’s ready to bring in blood tests for the endurance-boosting hormone EPO if the World Anti-Doping Agency deems them necessary.

The subject of doping in tennis has come to prominence during Wimbledon, with players and officials discussing what measures should be taken to combat use of banned substances.

WTA Tour spokesman Chris De Maria said the women’s tour has not done out-of-competition testing until now because of “budgetary constraints.” But he said the tour will conduct testing “the remainder of this year and definitely next year.”

“It was determined recently that we had the budget and the need to do it to make sure things are on the up and up,” he said.

Williams, the top-ranked player in the women’s game the and two-time defending Wimbledon champion, said she’s not against out-of-competition testing in general but is opposed to no-notice testing.

“I don’t think that’s a good idea,” she said. “I think there has to at least be a notice normally. I wouldn’t let anyone in my house if I’m not expecting them. Showing up at the door you kidding?”

Asked about drugs in tennis, Williams said, “I don’t think it’s a factor at all.” Capriati said she doesn’t think any players use steroids.

Capriati, a three-time Grand Slam title winner, expressed strong opposition to random, offsite testing.

“It’s news to me,” she said. “I think that’s a bit of an invasion. I don’t think they have any right to kind of see what’s going on inside your body, even if you’re not doing anything.”

When told some male players have tested positive in recent years, she said, “Well, the guys are another story.”

The WTA Tour’s chief legal officer, Tandy O’Donoghue, said the tour will proceed with the testing program no matter what the players think.

“Conducting out of competition testing is consistent with our rules,” she said.

“The rule is in place. The rule is the rule.”

O’Donoghue said testing would be run by the tour itself, not outside sports bodies.

Under the current Olympic-standard procedure for EPO, athletes undergo a combined blood-urine test. If the blood screen shows abnormal levels of red cells, the urine test is used to confirm a positive result.

Jevans said she anticipates WADA will decide in favor of a stand-alone urine test, with no blood samples involved.