The procedural step, in what has been a long-running and high-profile legal battle, was announced at a hearing in central London following a March decision to deny Australian-born Assange permission to appeal against his extradition.
The extradition order must now be signed by Patel, after which Assange can try to challenge the decision by judicial review. A judicial review involves a judge examining the legitimacy of a public body's decision.
Assange, 50, is wanted in the United States on 18 criminal charges, including breaking a spying law, after WikiLeaks published thousands of secret U.S. files in 2010.
He denies any wrongdoing.
Assange has been in a southeast London jail since 2019, and before that was holed up in the Ecuadorean Embassy in the British capital for seven years.