The NFL and the players' union remain at an impasse on HGH testing.

NFL lead counsel Jeff Pash tells The Associated Press on Wednesday that the World Anti-Doping Agency, which would conduct the testing, "demonstrated to our satisfaction that there is very sound science and very thoughtful testing protocols" during a meeting Wednesday in Montreal.

A person familiar with the talks says the union is not satisfied, however, with WADA's information on the procedures it uses and the reliability of the blood test. WADA handles drug testing for the Olympics and is largely accepted as the gold standard for worldwide drug testing.

The person spoke on condition of anonymity because the talks are supposed to be confidential.