Gerald Ford, the nation's oldest living former president, was in a hospital Thursday and undergoing medical tests, his office said.
Ford, 93, was doing well at Eisenhower Medical Center, spokeswoman Penny Circle said in a statement. She did not disclose the nature of the tests.
The former president has been hospitalized repeatedly this year.
He underwent heart procedures in August at the Mayo Clinic in Rochester, Minn., then returned to his home in Rancho Mirage. He received an implantable cardiac pacemaker to regulate his heartbeat and underwent angioplasty, with stents in two of his coronary arteries to increase blood flow.
In July, Ford was admitted to Colorado's Vail Valley Medical Center for a few days because of shortness of breath. In January, he was hospitalized for 12 days in Rancho Mirage to treat pneumonia.
Five years ago, Ford suffered two small strokes and spent about a week in a hospital.
Ford, a Michigan Republican, was House minority leader when President Nixon chose him to replace Spiro Agnew, who resigned, as vice president in 1973. Ford became president on Aug. 9, 1974, when Nixon resigned amid the Watergate scandal.