The Mayo Clinic was named the nation's No. 1 hospital by U.S. News & World Report on Tuesday, the first time the Minnesota medical giant has earned top honors in the magazine's annual ranking of adult care across 16 medical specialties.

Mayo, based in Rochester, edged out Massachusetts General Hospital in Boston for the top rung after Johns Hopkins Hospital in Baltimore ended its 21-year reign and fell to third place.

"This is a tremendous acknowledgment of the great work our staff does every day to deliver high quality, affordable health care for our patients," said Dr. John Wald, medical director for public affairs and marketing at Mayo.

"While no single set of measures can perfectly represent health care quality, we are proud to be recognized for the work we do," Wald added.

The U.S. News index, begun in 1990, is just one of many national rankings of hospital quality and care, but it's gold for marketers and is certain to burnish Mayo's already distinguished reputation.

The 2014-2015 list of 4,743 hospitals was published Tuesday.

The rankings exclude routine care in hospitals, and don't consider cost as a factor in the analysis. The magazine cautions consumers that the rankings are only a starting point, and urges further research specific to each patient.

The index considers a hospital's reputation among specialists, in addition to survival rates, patient safety and other care-related indicators such as nursing and clinically-proven technology.

Of the nearly 5,000 hospitals analyzed, just 144 facilities ranked among the top in at least one of the 16 specialties analyzed. Mayo Clinic ranked No. 1 in half of the specialties.

The index also provides state and regional rankings. Abbott Northwestern Hospital in Minneapolis ranked second in the state, with four nationally ranked specialties, followed by Mercy Hospital in Coon Rapids, with one nationally ranked specialty.

The University of Minnesota Medical Center, Fairview, ranked fourth statewide, with no nationally ranked specialties but 12 listed as "high-performing."

The index is based on data for a dozen specialties: cancer; cardiology and heart surgery; diabetes and endocrinology; ear, nose and throat; gastroenterology and gastrointestinal surgery; geriatrics; gynecology; nephrology; neurology and neurosurgery; orthopedics; pulmonology; and ­urology.

In addition, ophthalmology, psychiatry, rehabilitation and rheumatology are evaluated as reputation measures.

Federal facilities were not included in the analysis because of the difficulty in ­getting data, the magazine said.