White House chief of staff Jeff Zients is launching a review of Cabinet protocols for delegating authority in the wake of Defense Secretary Lloyd Austin's secret hospitalization, according to a memo obtained by Axios.

Why it matters: The Pentagon is under growing pressure from members of Congress to disclose how and why White House officials — including President Biden — were not informed of Austin's Jan. 1 hospitalization for more than three days.

• Austin, who remains in the hospital but is no longer in the intensive care unit, has no plans to resign despite calls for his ouster from some Republicans.
• Biden has indicated he has full confidence in his defense secretary, but Zients is seeking to ensure the breakdown in communication and transparency is not repeated.

Details: Zients' memo, addressed to all Cabinet secretaries, directs departments and agencies to "submit your existing protocols for a delegation of authority" for review by Jan. 12.

• While the White House conducts its review, Zients is reminding Cabinet agencies that they must adhere to certain procedures when delegation of authority is required.
• That includes notifying the White House, activating existing delegation-of-authority protocols and documenting everything in writing.
• The memo does not mention Austin's hospitalization.

The protocols will be scrutinized to ensure they address:

• Delegation criteria
• Decision-making authority
• Applicable documentation
• Notification procedures
• Rescission of delegation

The big picture: Zients' memo follows one sent by the Department of Defense yesterday that directed an internal review of the processes and procedures during Austin's hospitalization.

What we know: Pentagon press secretary Maj. Gen. Pat Ryder told reporters Monday that Austin underwent an elective procedure on Dec. 22, which the White House was also not aware of.

• Austin was then transported to the hospital via ambulance on Jan. 1 after experiencing "severe pain."
• Some of Austin's authorities were transferred on Jan. 2 to Deputy Defense Secretary Kathleen Hicks, who was vacationing in Puerto Rico and not aware of his hospitalization.
• Hicks and the White House were finally notified of Austin's hospitalization on Jan. 4. Ryder said Austin's chief of staff was out sick with the flu, which "caused a delay in these notifications."

What they're saying: "I offer my apologies and my pledge to learn from this experience. I will do everything I can to meet the standard you expect from us," Ryder told the Pentagon press corps.

Read the full memo.