Updated

Former first lady Nancy Reagan was undergoing tests Monday at a hospital after spending a precautionary night there for a fall she took in her Bel-Air home, her spokeswoman said.

Reagan, 86, was doing well after falling on Sunday morning, spokeswoman Joanne Drake said.

"She's doing fine. She had a good breakfast this morning. She's in good spirits," Drake said.

It wasn't immediately clear when Reagan would be released from St. John's Health Center, where doctors determined she did not break a hip as feared, Drake said.

Reagan spent the night in the same room where former President Ronald Reagan stayed after he broke his hip at home in 2001. He died June 5, 2004, after a 10-year battle with Alzheimer's disease. The two were married for 52 years.

Nancy Reagan's last major public appearance was at the Jan. 30 Republican presidential debate at the Reagan Library in Simi Valley, Calif., where she sat with Gov. Arnold Schwarzenegger.

She did not attend a 97th birthday celebration held for her late husband at the library on Feb. 6.