Patients at Mount Sinai Medical Center are able to carry their medical records in their wallets, thanks to new “smart” identification cards the hospital is distributing.

Each card, which is the size and shape of a credit card, features a digital image of the patient and contains a computer chip that is capable of storing 33 pages of data. Designed to help the hospital correctly identify patients, the cards also consolidate each patient’s medical history, which can be accessed anywhere in the hospital — from its outpatient clinics to the emergency room.

“It’s kind of like an ATM card for your health data,” a project manager in the hospital’s department of information technology, Justin DuPont, said.

The cards were first issued to patients at Elmhurst Hospital Center, a public hospital in Queens that is affiliated with Mount Sinai, and to patients at Mount Sinai Hospital of Queens and Settlement Health, a clinic affiliated with Mount Sinai. Currently, about 2,000 Mount Sinai patients have “smart” cards, and hospital officials said their goal is to issue them to 10,000 patients, or about 10% of the hospital’s patient base.

As hospitals and doctors increasingly turn to electronic medical records, Mount Sinai officials said they initially became interested in the cards as a way to ensure staff members were using the correct medical histories for patients, especially those with common names.

“We may have a Juan Gonzalez in the hospital today,” Mr. DuPont said. “I can do a search and we’ll probably come up with 500 patients in our database whose name is Juan Gonzalez.”

He offered a recent example of twins whose medical records were accidentally combined. The error occurred when one twin, named Phillipe, came to the hospital and an administrator confused him with his sibling, Phillipo. The administrator, who observed the same last name, address, birth date, and mother on the two records, believed there was a typo, Mr. DuPont said. “There was nothing in the records saying Phillipe was a twin,” he said. With a “smart” card, however, “the patient is bringing in something that really identifies them.”

On a recent afternoon, hospital employees ironed out the kinks in the new system when a patient arrived to receive her “smart” identification card.

As the patient, Doris Martin, settled into a chair to have her photograph taken, a hospital registrar, Lois Kern, trained the camera on her subject and said she would take six photos for the patient to choose from.

“Make it seven, for the lucky no. 7,” Ms. Martin, who was smoothing down her hair, joked. As Ms. Kern completed her card, Ms. Martin peppered her with questions about card security, among other things. Before Ms. Martin left, she expressed relief that the card would better enable the hospital to keep track of the medicine she takes for high blood pressure and know about her allergy to penicillin. “Everything that saves you time is great,” she added.

According to hospital officials, each card contains a 64K memory chip that stores a patient’s medical history. The cards also have bar codes and magnetic strips that hospital officials said might someday be used for financial transactions.

“We’ve even been kicking around the idea of putting an EKG on the card so that if you come in we can do an EKG and compare it to the one on the card,” the hospital’s senior vice president and chief information officer, Jack Nelson, said.

To ensure confidentiality, patient information is encrypted. In the near future, card readers will be installed and activated around the hospital, and patients will be asked to enter a personal identification number on a keypad when they present their cards.

Hospital officials said that in addition to helping identify patients, the cards will reduce clerical and billing errors. According to Mr. DuPont, the hospital accumulates $1 million in contested claims each week, partly because of administrative mistakes. “So it’s really important to be able to identify patients much more clearly, identify who they are, where they’re covered,” he said.

The cards also play a role in ensuring patient safety. For patients who cannot speak because of illness or for patients who do not know what medications they are taking, the cards communicate that information for them.

While “smart” cards have been used in other industries — including transportation and banking — they have been introduced more recently to the health care field, according to the executive director of the Smart Card Alliance, Randy Vanderhoof. So far, a number of hospitals have launched such systems, including the University of Pennsylvania Medical Center and St. Luke’s Episcopal Health System in Houston.

More facilities are likely to follow, as hospitals look at new ways to protect patient data, Mr. Vanderhoof said. “This is the perfect environment for smart card technology,” he said.

At Mount Sinai, officials said they envision a network of New York hospitals that use the technology, enabling patients with “smart” cards to access their medical records at all participating medical centers. Such a network would be helpful in emergency situations, in particular. “The idea is that this thing would grow the way automatic teller machines did,” Mr. Nelson said.