July 17, 2009 -- U.S. News & World Report has released its annual "honor roll" of America's best medical centers, and Johns Hopkins Hospital in Baltimore is at the top of the list for the 19th straight year.

The top 21 hospitals all earned high scores in at least six of 16 specialties, ranging from cancer and geriatric care to orthopaedics and urology.

Scores were based on both objective measures -- such as mortality rates, patient safety, and other care-related factors -- and subjective measures, such as reputation.

"I think these rankings are extremely meaningful to an extremely small number of patients, relatively speaking, who represent a very small piece of the patient population but whose need for a very high quality of care is extreme," Avery Comarow, the U.S. News & World Report statistician who compiled and analyzed the data, tells WebMD. "These rankings are not at all intended for those who need relatively routine procedures."