The N.B.A.’s new collective bargaining agreement opens the door to blood testing for human growth hormone — provided that the league and the players union can agree on the reliability of the test.

Major League Baseball became the first major professional sports league in North America to approve testing for H.G.H. when its owners and players signed off on a new labor deal last month. The N.B.A. could become the second, but hurdles remain.

Mike Bass, a spokesman for the N.B.A., said Wednesday that the union and the league have agreed to H.G.H. testing “subject to the test being validated by a neutral committee of experts.”