The NFL and the players’ union remain at odds over the sport’s planned blood-testing program for human growth hormone, even after a meeting with congressional leaders last week on Capitol Hill.

The union announced Wednesday that it had rejected a proposal by the league to begin having blood drawn from players Monday.

“We informed the NFL yesterday that absent a collective agreement on several critical issues, blood collection is not ready to be implemented on Monday,” a written statement issued by the union said. “We have advised the players.”

The ongoing stalemate means the two sides soon could have another meeting with leaders of the House committee on oversight and government reform.

Representatives of the league and union met Friday with that committee’s leaders. Rep. Darrell Issa (R-Calif.), the committee’s chairman, and Rep. Elijah Cummings (D-Md.), the ranking Democrat on the committee, announced after the meeting that blood would be drawn from players soon while the league and union would continue to work out the details of the testing program.

Issa and Cummings said after Friday’s meeting there would be a follow-up meeting in 30 days but that meeting would come sooner, perhaps in two weeks or less, if the league and union were unable to agree on a plan to start the testing.

NFL Commissioner Roger Goodell said Friday that the league would comply with Issa’s request to begin drawing blood from players within two weeks. This week, the league has put a specific timetable on that.

“We have notified the union that we are ready to start collecting blood samples on Monday,” Greg Aiello, the NFL’s senior vice president of communications, said Wednesday.

If blood is drawn from players, it would not necessarily be tested immediately for HGH. One possibility raised last week is that the blood samples would be taken and preserved, and tested only after a deal is struck on the testing program.

Union representatives said Friday they would agree to allow the testing program to begin only after they are satisfied that the HGH testing is reliable and safe.

The league and union agreed as part of their 10-year labor deal completed in August to begin testing players for HGH. They targeted the beginning of the regular season in early September to start the testing. But the testing has been on hold because the labor deal says the two sides first must agree on the particulars of the testing program and those negotiations have been stalemated.